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  • Analytical Chemistry and Spectroscopy  (25,705)
  • Engineering  (11,657)
  • transformation
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  • 1
    Electronic Resource
    Electronic Resource
    The changing geography of morbidity and mortality in post-communist Poland (2000)
    Springer
    GeoJournal 50 (2000), S. 97-100 
    Details
    ISSN: 1572-9893
    Keywords: disease ; health ; morbidity ; mortality ; pollution ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract In general, the health of Poles improved markedly in the thirty years after the Second World War, but there was some deterioration after 1989 before improvement resumed. Only in the case of cancer is there an upward trend and so Poles are now healthier than they have been at any time in the past. However there are sharp regional variations well exemplified by the incidence of tuberculosis, where there appears to be some correlation with poorer housing and atmospheric pollution. High death rates in Lodz (consistently the highest in the country at the voivodship level between 1989 and 1996), may also be linked with environmental pollution as well as the ageing of the population. Variations between town and country are small, but Poland shows up in a poor light when compared with other European countries. These are important issues for the administration and financing of the welfare services.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007127431508
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  • 2
    Electronic Resource
    Electronic Resource
    A computational procedure for joining separate map sheets (2000)
    Springer
    GeoJournal 52 (2000), S. 253-262 
    Details
    ISSN: 1572-9893
    Keywords: map sheets ; GIS ; seamless spatial database ; transformation ; computational procedure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract Map sheets have been often used as a basic spatial unit for managing spatial data produced from paper maps. This often results in incompatibility between adjacent map sheets, because spatial objects do not cross the boundaries smoothly and even the boundaries themselves do not match their neighbors exactly. To solve the problem this paper proposes a computational procedure for joining separate map sheets to obtain seamless spatial data. Line objects digitized separately in different map sheets are considered, which are frequently used to represent road networks, gas pipelines, and boundaries of polygon objects. The procedure consists of three steps: (1) extraction of end nodes, (2) detection of matching nodes, and (3) transformation of the map sheet. Each step goes interactively so that unexpected errors can be avoided by human observation. To test the validity of the procedure, map sheets are combined containing the road network data of Tokyo 23-ku area, Japan.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1014224325346
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  • 3
    Electronic Resource
    Electronic Resource
    Socioeconomic transformation in rural Romania through the eyes of experts: Demographic and social issues (2000)
    Springer
    GeoJournal 50 (2000), S. 151-155 
    Details
    ISSN: 1572-9893
    Keywords: demography ; experts ; rural ; Romania ; rural development ; social issues ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract There is no standard model of transformation for post- socialist countries and each country encounters specific problems rooted in the geographical characteristics of the areas concerned. The human resources are of the greatest importance because it really matters how people (especially the decision-makers) perceive system change and continually reformulate their expectations and strategies; so investigations into the views of people caught up in the transformation can provide a deeper understanding of the background to structural change. Working the national, regional level and local levels in Romania, experts were asked to consider the advantages and disadvantages arising out of the transformation, the most important problems and constraints for future rural development and the policies needed. The paper examines the responses on demographic and social issues. It emerges the most detailed responses were supplied by local-level representatives while respondents at the regional level steered a middle course between the need to address local problems and the prime importance of stimulating the Romanian economy so as to generate resources for welfare programmes (with the latter issue the overriding concern of interviewees at national level). There was general agreement on the importance of foreign investment and European integration for economic development, with local actors taking only small steps in line with the existing opportunities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007120608735
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  • 4
    Electronic Resource
    Electronic Resource
    Transformation of batridene (2000)
    Springer
    Chemistry of natural compounds 36 (2000), S. 137-139 
    Details
    ISSN: 1573-8388
    Keywords: 1,1′,6,6′,7,7′-hexahydroxy-3,3′-dimethyl-5,5′-diisopropyl-2,2′-dinaphthylidene-8,8′-dibarbituric acid ; transformation ; DMSO
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Transformations of 1,1′,6,6′,7,7′-hexahydroxy-3,3′-dimethyl-5,5′-diisopropyl-2,2′-dinaphthylidene-8,8′-dibarbituric acid (batridene) in DMSO are studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02236415
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  • 5
    Electronic Resource
    Electronic Resource
    Metal resistance in Pseudomonas strains isolated from soil treated with industrial wastewater (2000)
    Springer
    World journal of microbiology and biotechnology 16 (2000), S. 177-182 
    Details
    ISSN: 1573-0972
    Keywords: Conjugation ; metal resistance ; plasmid DNA ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Heavy metal concentrations in soil treated with industrial wastewater of Aligarh City (U.P.), India were determined. The analysis of test samples revealed high levels of Fe, Zn, Ni and Cu. A total of 45 Pseudomonas spp. were isolated from soil and were characterized on the basis of morphological, cultural and biochemical characteristics. MICs of Hg2+, Cd2+, Cu2+, Cr3+, and Zn2+ for each isolate were determined. Eighty percent of the strains isolated from soil harboured resistance to copper, whereas 73.3% of the isolates exhibited resistance to cadmium, 71.1% to chromium and zinc and 48.8% to mercury. A maximum MIC of 200 μg/ml for mercury and 1600 μg/ml for other metals was observed. Metal resistance was found to be plasmid mediated as evidenced by transformation studies. Further, the transmissible nature of chromium resistance was confirmed by conjugation. Agarose gel electrophoresis using the miniprep method for plasmid isolation revealed that these isolates harboured plasmids of molecular weights (45 & 47 kb) using EcoRI and HindIII digests of λDNA and undigested λDNA as standard markers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008905902282
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  • 6
    Electronic Resource
    Electronic Resource
    The effect of DNA/gold particle preparation technique, and particle bombardment device, on the transformation of barley (Hordeum vulgare) (2000)
    Springer
    Euphytica 111 (2000), S. 67-76 
    Details
    ISSN: 1573-5060
    Keywords: Barley ; Hordeum vulgare ; transformation ; particle bombardment ; particle gun
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Immature embryos of the spring barley variety GoldenPromise, were bombarded with three different particledelivery systems and both transient and stabletransformation examined. In addition, a range oftechniques for the preparation of the DNA coated goldparticles was examined. Fertile transgenic barleyplants were obtained using three particle preparationtechniques which differed in the amount of gold andDNA used for each bombardment. However, only one ofthe particle delivery systems, the PDS 1000/He device,appeared to be effective in yielding transformedbarley plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003700300235
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  • 7
    Electronic Resource
    Electronic Resource
    Towards genetic transformation in the monocot Alstroemeria L. (2000)
    Springer
    Euphytica 115 (2000), S. 17-26 
    Details
    ISSN: 1573-5060
    Keywords: cell suspension ; monocotyledon ; selection ; somatic embryogenesis ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The successful application of plant biotechnology to Alstroemeria improvement will largely depend on the availability of an efficient regeneration/transformation system. Regeneration in Alstroemeria is accomplished from nodular embryogenic callus initiated from zygotic embryos. Histological studies of embryogenic callus initiation from 4-weeks old cultured ovules revealed that the outermost layers of the protoderm of the embryogenic nodules divided to form either a new nodule or aproembryo. Transient gene expression after particle bombardment of nodular embryogenic callus was optimized using DNA of pAHC25. The highest β-glucuronidase expression was found when the GUS gene was under control of the maize ubiquitin promoter, the target tissue was placed 5 cm below the microcarrier launch assembly and when the rupture disc-breakage point was between 650–900 psi. Kanamycin blocked regeneration of somatic embryos, however, did not block growth of nodular embryogenic callus. With phosphinothricin both callus growth and regeneration were blocked. Bombardment of nodular embryogenic callus with DNA of pAHC25 combined with selection on medium containing phosphinothricin resulted in putative transgenic chimeric. Friable calli were selected from nodular embryogenic callus and used to initiate suspensions. These cell suspensions were subjected to transformation by particle bombardment using DNA of pAHC25 and resulted in a stable transformed friable callus line after selection based on luciferase activity. Even after 2 years of maintenance this callus line was luciferase positive and the Polymerase Chain Reaction analysis demonstrated the presence of the introduced gene in this friable callus line.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003979423469
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  • 8
    Electronic Resource
    Electronic Resource
    Rapid transformation and regeneration of alfalfa (Medicago falcata L.) via direct somatic embryogenesis (2000)
    Springer
    Plant growth regulation 31 (2000), S. 155-166 
    Details
    ISSN: 1573-5087
    Keywords: alfalfa ; cell division cycle ; somatic embryogenesis ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two simple, rapid and efficient protocols for theregeneration of transformed tetraploid lines ofalfalfa (Medicago falcata L.) have beendeveloped and compared. Leaf explants fromembryogenic lines 47/1-150 and 47/1-5 were inoculatedwith Agrobacterium tumefaciens containingconstructs carrying the nptII selectable markergene and promoter:gusA gene fusions under thecontrol of the CaMV 35S or Arabidopsis cdc2a,CycB1 and CycA2 promoters. In the firstregeneration system (the MSH system), inoculated leafexplants were incubated on MS medium supplemented with2,4-D and kinetin and then subcultured onto plantgrowth regulator-free MS medium in order to inducedirect somatic embryogenesis. In the secondregeneration system (the B5h system), the inoculatedexplants were incubated on B5h medium to induceindirect production of somatic embryos viaembryogenic callus. In both systems, an effectivekanamycin selection regime was employed and wasmaintained when the embryos were subcultured onto arecovery medium (Boi2Y) to promote further embryodevelopment. The use of Boi2Y medium was particularlyimportant for shortening the regeneration time andpromoting a higher frequency of healthy plantletproduction from the somatic embryos. The maturesomatic embryos were finally transferred to plantgrowth regulator-free MS medium for plantletformation. Transgenic plantlets were produced within10–14 weeks in the MSH system and 12–16 weeks in theB5h system. The MSH system appears to be the fastesttransformation system reported for leguminous speciesto date. Confirmation of transformation was obtainedusing a re-callusing assay on kanamycin and subsequentSouthern blot hybridisation and PCR analysis. Theability to induce expression of GUS activity in leafexplants containing the cell division cycle genepromoter:gusA constructs by 2,4-D treatment alsoproved to be a reliable indicator of transformation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006306909722
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  • 9
    Electronic Resource
    Electronic Resource
    The Effects of Molybdenum on the High-Temperature Oxidation Resistance of Thin Foils of Fe–20Cr–5Al at Very High Temperatures (2000)
    Springer
    Oxidation of metals 53 (2000), S. 561-576 
    Details
    ISSN: 1573-4889
    Keywords: Fe–Cr–Al alloy ; oxidation ; molybdenum ; breakaway oxidation ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Thin foils of Fe–20Cr–5Al alloys are susceptible to breakawayoxidation once the aluminum content of the substrate has fallen below somecritical value. The combined addition of 0.1 wt.% lanthanum and 0, 1, or 2wt% molybdenum has a beneficial effect on the high-temperature oxidation ofsuch foils. Lanthanum has the well-known reactive-element effect on adhesionof the protective alumina scale, thereby increasing the time to onset ofbreakaway oxidation, while, for alloys containing molybdenum, breakawayoxide spreads relatively slowly over the specimen in comparison to alloysthat contain no molybdenum. In particular, molybdenum-containing alloys areable to develop a protective Cr2O3 layer at the breakawayoxide–substrate interface. Conversely, molybdenum-free alloys form aninternal-oxide zone in the substrate adjacent to this interface, rather thana Cr2O3 layer, so breakaway oxide spreads rapidly. A martensitic phase isobserved in the substrate adjacent to the breakaway oxide formed on Fe–20Cr–5Al–La specimens, which means that theα-phase has transferred to the γ -phase at the temperature ofthe oxidation test (1150°C). Conversely, α-phase is retained inthe molybdenum-containing alloy, even after breakaway takes place, sincemolybdenum, which is a strong ferrite former, is enriched in the alloyadjacent to areas of breakaway oxide. The diffusion rate of chromium isslower in the γ than in the α-phase so a continuouschromium-rich oxide layer, which is effective in inhibiting breakawayoxide from spreading, cannot be established at the breakawayoxide–substrate interface for the molybdenum-free alloys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004689211302
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  • 10
    Electronic Resource
    Electronic Resource
    Factors involved in Agrobacterium tumefaciens-mediated gene transfer into Pinus nigra Arn. ssp. salzmannii (Dunal) Franco (2000)
    Springer
    Euphytica 114 (2000), S. 195-203 
    Details
    ISSN: 1573-5060
    Keywords: conifers ; salgareño pine ; tissue culture ; transformation ; transient gene expression ; uidA expression ; vir gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Cotyledons from dissected sterile embryos of salgareño pine (Pinus nigra Arn. ssp. salzmannii (Dunal) Franco) were inoculated with different disarmed Agrobacterium tumefaciens strains harbouring the binary vector p35SGUSint. The transient expression of a β-glucuronidase gene (uidA) was studied, using a histochemical staining procedure. Nineteen days after inoculation, the activity of β-glucuronidase was detected in epidermal and subepidermal layers of cotyledonary explants. The EHA105 strain harbouring a disarmed agropine-type Ti-plasmid (pTiBO542) was the most effective for gene transfer of the uidA gene. The effects of exudates and extracts from 0-day-old embryos on induction of vir gene expression in A. tumefaciens were also examined. The results of this study showed that salgarño pine embryo exudates contain a substance(s) that induce vir gene expression, in similar way to that observed with 100 μM acetosyringone (AS).All these findings suggest that T-DNA processing and transfer might take place when Agrobacterium infects suitable tissues of salgareño pine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003946131356
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  • 11
    Electronic Resource
    Electronic Resource
    Metamorphosis of a Non-Functioning Pituitary Adenoma to Cushing's Disease (2000)
    Springer
    Pituitary 3 (2000), S. 117-122 
    Details
    ISSN: 1573-7403
    Keywords: Cushing's disease ; silent ; pituitary ; tumour ; macroadenoma ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Silent pituitary adenomas occur in 25–40% of all clinically apparent pituitary tumours. However, the subsequent development of florid Cushing's disease in a patient with a previous non-functioning tumour is extremely rare. We describe a 47 year-old woman presenting initially with a large, invasive and recurrent, non-functioning pituitary tumour. Histopathologic study of the initial tissue did not stain for any hormones. Six years after the initial presentation, she manifested florid ACTH dependent Cushing's syndrome. A recurrent invasive pituitary macroadenoma necessitated a third transphenoidal surgery. The resected specimen, in this instance, revealed positive staining for ACTH, FSH, prolactin, and growth hormone on immunocytochemistry. An incomplete response to surgical, radiation and medical therapy necessitated a bilateral adrenalectomy to control the hypercortisolism, which resulted in remarkable clinical improvement. We also review five previous case reports from the revision literature of similar transformations from non-secreting pituitary adenomas to Cushing's disease. This subset of patients may represent yet another entity in the widening spectrum of Cushing's syndrome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009961925780
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  • 12
    Electronic Resource
    Electronic Resource
    Floral Spray Transformation Can Efficiently Generate Arabidopsis (2000)
    Springer
    Transgenic research 9 (2000), S. 471-486 
    Details
    ISSN: 1573-9368
    Keywords: Arabidopsis thaliana ; Agrobacterium tumefaciens ; floral spray ; SOD ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this study, floral spray and floral dip were used to replace the vacuum step in the Agrobacterium-mediated transformation of a superoxide dismutase (SOD) gene into Arabidopsis. The transgene was constructed by using a CaMV 35S promoter to drive a rice cytosolic CuZnSOD coding sequence in Arabidopsis. The transgene construct was developed in binary vectors and mobilized into Agrobacterium. When Arabidopsis plants started to initiate flower buds, the primary inflorescence shoots were removed and then transformed by floral spray or floral dip. More than 300 transgenic plants were generated to assess the feasibility of floral spray used in the in planta transformation. The result indicates that the floral spray method of Agrobacterium can achieve rates of in planta transformation comparable to the vacuum-infiltration and floral dip methods. The floral spray method opens up the possibility of in planta transformation of plant species which are too large for dipping or vacuum infiltration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026522104478
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  • 13
    Electronic Resource
    Electronic Resource
    Efficient Production of Transgenic Cassava Using Negative and Positive Selection (2000)
    Springer
    Transgenic research 9 (2000), S. 405-415 
    Details
    ISSN: 1573-9368
    Keywords: Manihot esculenta ; transformation ; Agrobacterium tumefaciens ; mannose ; hygromycin ; selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to improve the efficiency of cassava (Manihot esculenta Crantz) transformation, two different selection systems were assessed, a positive one based on the use of mannose as the selective agent, and a negative one based on hygromycin resistance encoded by an intron-containing hph gene. Transgenic plants selected on mannose or hygromycin were regenerated for the first time from embryogenic suspensions cocultivated with Agrobacterium. After the initial selection using mannose and hygromycin, 82.6% and 100% of the respective developing embryogenic callus lines were transgenic. A system allowing plant regeneration from only transgenic lines was designed by combining chemical selection with histochemical GUS assays. In total, 12 morphologically normal transgenic plant lines were produced, five using mannose and seven using hygromycin. The stable integration of the transgenes into the nuclear genome was verified using PCR and Southern analysis. RT-PCR and northern analyses confirmed the transgene expression in the regenerated plants. A rooting test on mannose containing medium was developed as an alternative to GUS assays in order to eliminate escapes from the positive selection system. Our results show that transgenic cassava plants can be obtained by using either antibiotic resistance genes that are not expressed in the micro-organisms or an antibiotic-free positive selection system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026509017142
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  • 14
    Electronic Resource
    Electronic Resource
    Two types of new algorithms for finding explicit analytical solutions of nonlinear differential equations (2000)
    Springer
    Applied mathematics and mechanics 21 (2000), S. 1423-1431 
    Details
    ISSN: 1573-2754
    Keywords: nonlinear differential equations ; transformation ; algorithm ; analytical solution ; O175.29
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Mathematics , Physics
    Notes: Abstract The idea of AC=BD was applied to solve the nonlinear differential equations. Suppose that Au=0 is a given equation to be solved and Dv=0 is an equation to be easily solved. If the transformation u=Cv is obtained so that v satisfies Dv=0, then the solutions for Au=0 can be found. In order to illustrate this approach, several examples about the transformation C are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02459221
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  • 15
    Electronic Resource
    Electronic Resource
    Transgenic Trifolium repens with foliage accumulating the high sulphur protein, sunflower seed albumin (2000)
    Springer
    Transgenic research 9 (2000), S. 103-113 
    Details
    ISSN: 1573-9368
    Keywords: inheritance ; Rubisco small subunit promoters ; sonication ; sulphur nutrition ; sunflower albumin ; transformation ; white clover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract With the aim of increasing the rumen-protected level of the sulphur amino acids cysteine and methionine in Trifolium repens, we introduced the coding sequence of the sunflower seed albumin (SSA) into T. repens by Agrobacterium tumefaciens-mediated transformation. The SSA gene was modified such that the protein would be localised to the endoplasmic reticulum (ER). Four different T-DNA constructions all containing the SSA gene driven by either the promoter of a gene encoding the small subunit of ribulose bisphosphate carboxylase (Rubisco) from Arabidopsis thaliana (A ssu), the promoter of the gene encoding the small subunit of Rubisco of Medicago sativa (L ssu), or the Cauliflower Mosaic Virus 35S promoter (CaMV35S), were transferred to T. repens cv. Haifa. Transgenic T 0-plants and inter-transgenic hybrids were analysed for the level of SSA accumulation in the leaves by western blotting. The highest observed level of SSA accumulation was 0.1% of total extractable leaf protein. We observed that the promoter had a substantive effect on the level of SSA accumulation with A ssu〉CaMV35S〉L ssu. Results from the inter-transgenic hybrids showed that the capacity to synthesise SSA was inherited. However the level of SSA accumulation in the leaves generally appears not to be additive with extra transgenic loci. During this work, we attempted to improve the efficiency of A. tumefaciens-mediated transformation of T. repens using the SAAT-method (Sonication Assisted Agrobacterium-mediated Transformation) on cotyledons of T. repens. T-DNA transfer was in general not enhanced by sonication compared to traditional A. tumefaciens-mediated transformation. Furthermore, Southern blot analyses of plants regenerated from the same cotyledon after A. tumefaciens treatment and under selection, indicated that multiple shoots were usually derived from the same transformation event. We concluded from these results that only one plant from each A. tumefaciens-treated cotyledon should be taken to avoid transgenic clones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008967409302
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  • 16
    Electronic Resource
    Electronic Resource
    Transformation of the tropane alkaloid-producing medicinal plant Hyoscyamus muticus by particle bombardment (2000)
    Springer
    Transgenic research 9 (2000), S. 163-168 
    Details
    ISSN: 1573-9368
    Keywords: Hyoscyamus muticus ; particle bombardment ; transformation ; tropane alkaloids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We report an efficient whole plant transformation system for Hyoscyamus muticus, an important medicinal plant of the Solanaceous family. We developed a system using a plasmid carrying the nptII and gusA genes, which was delivered into leaf explants by particle bombardment. Ten percent of bombarded leaf explants formed kanamycin-resistant callus, from which putative transgenic plants were recovered. The nptII gene conferring kanamycin resistance was found to be incorporated into the genome of all transgenic plants screened. Over 50% of the kanamycin resistant plants showed strong expression of the non-selected gusA gene. The majority of transgenic plants reached maturity, could be self pollinated, and produced fertile seed. A simple and efficient whole plant transformation system for this medicinal plant is an important step in furthering our understanding of tropane alkaloid production in plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008912330067
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  • 17
    Electronic Resource
    Electronic Resource
    Enhanced forskolin production in genetically transformed cultures of Coleus forskohlii by casein hydrolysate and studies on growth and organisation (2000)
    Springer
    Biotechnology letters 22 (2000), S. 133-136 
    Details
    ISSN: 1573-6776
    Keywords: casein hydrolysate ; Coleus forskohlii ; forskolin ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Casein hydrolysate at 2.0 g l−1 significantly enhanced forskolin content (2.3 mg g−1 cell dry wt) in a rhizogenic tumourous line, GCO-RCH-2 of Coleus forskohlii. In rooty teratoma line, RC-ST-2/4, forskolin content enhanced to 1.7 mg g−1 cell dry wt in presence of 2.5 g l−1 casein hydrolysate. Unlike untransformed calli and rhizogenic/root cultures, all the forskolin yielding transformed cultures of C. forskohlii have been maintained for over 5 years.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005618307074
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  • 18
    Electronic Resource
    Electronic Resource
    Agrobacterium-mediated sorghum transformation (2000)
    Springer
    Plant molecular biology 44 (2000), S. 789-798 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium tumefaciens ; sorghum ; transformation ; transgenic plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Agrobacterium tumefaciens was used to genetically transform sorghum. Immature embryos of a public (P898012) and a commercial line (PHI391) of sorghum were used as the target explants. The Agrobacterium strain used was LBA4404 carrying a `Super-binary' vector with a bar gene as a selectable marker for herbicide resistance in the plant cells. A series of parameter tests was used to establish a baseline for conditions to be used in stable transformation experiments. A number of different transformation conditions were tested and a total of 131 stably transformed events were produced from 6175 embryos in these two sorghum lines. Statistical analysis showed that the source of the embryos had a very significant impact on transformation efficiency, with field-grown embryos producing a higher transformation frequency than greenhouse-grown embryos. Southern blot analysis of DNA from leaf tissues of T0 plants confirmed the integration of the T-DNA into the sorghum genome. Mendelian segregation in the T1 generation was confirmed by herbicide resistance screening. This is the first report of successful use of Agrobacterium for production of stably transformed sorghum plants. The Agrobacterium method we used yields a higher frequency of stable transformation that other methods reported previously.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026507517182
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  • 19
    Electronic Resource
    Electronic Resource
    Bringing “The Dead” to Life: Reading James Joyce (2000)
    Springer
    Journal of applied psychoanalytic studies 2 (2000), S. 109-115 
    Details
    ISSN: 1573-3459
    Keywords: James Joyce ; “The Dead” ; fiction ; reading ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Psychology
    Notes: Abstract The author offers a personal reading of James Joyce's “The Dead.” She focuses on how the sounds of the language are used to portray the main character's deadness and his beginning to come to life once the barriers to inner self and self-knowledge are broken.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010193724350
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  • 20
    Electronic Resource
    Electronic Resource
    Changes in lipid and protein constituents of rafts and caveolae in multidrug resistant cancer cells and their functional consequences (2000)
    Springer
    Glycoconjugate journal 17 (2000), S. 253-259 
    Details
    ISSN: 1573-4986
    Keywords: Cancer ; caveolae ; caveolin ; cholesterol ; glucosylceramide ; multidrug resistance ; rafts ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The carcinogenic process involves a complex series of genetic and biochemical changes that enables transformed cells to proliferate, migrate to secondary sites and, in some cases, acquire mechanisms that make cancer cells resistant to chemotherapy. This phenomenon in its most common form is known as multidrug resistance (MDR). It is usually mediated by overexpression of P-glycoprotein (P-gp) or other plasma membrane ATPases that export cytotoxic drugs used in chemotherapy, thereby reducing their efficacy. However, additional adaptive changes are likely to be required in order to confer a full MDR phenotype. Recent studies have shown that acquisition of MDR is accompanied by up-regulation of lipids and proteins that constitute lipid rafts and caveolar membranes, notably glucosylceramide and caveolin. These changes may be related to the fact that in MDR cells a significant fraction of cellular P-gp is associated with caveolin-rich membrane domains, they may be involved in drug transport and they could have an impact on drug-induced apoptosis and on the phenotypic transformation of MDR cancer cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026553626537
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  • 21
    Electronic Resource
    Electronic Resource
    Study of the factors influencing Agrobacterium-mediated transformation of pea (Pisum sativum L.) (2000)
    Springer
    Molecular breeding 6 (2000), S. 185-194 
    Details
    ISSN: 1572-9788
    Keywords: Agrobacterium ; transformation ; pea ; Pisum sativum L. ; PCR analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Factors influencing the efficiency of Agrobacterium-mediated transformation of pea were tested using highly efficient, direct regeneration system. The virulence of three Agrobacterium strains (octopine LBA 4404, nopaline C58C1 and succinamopine, hypervirulent EHA 105) clearly varied giving 1 transgenic plant per 100 explants for LBA 4404, 2.2 for C58C1 and 8.2 for EHA 105. To test the efficacy of selection agents we used the hypervirulent EHA 105 strain carrying pGPTV binary vector with one of four different selection genes: nptII, hpt, dhfr or bar. The mean number of transgenic, kanamycin-resistant plants for two cultivars tested was 4.2 per 100 explants and was slightly higher than the number of phosphinothricin-resistant plants (3.6 plants per 100 explants). The proportion of transgenics among kanamycin-selected plants was also higher than among phosphinothricin-resistant plants (35% and 28% respectively). There was no regeneration on hygromycin or methotrexate media (transformation with hpt and dhfr genes). Acetosyringone had no apparent influence on efficiency of transformation with hypervirulent EHA 105 strain, however it did affect the rate of transformation when moderately virulent C58C1 was used. Recovery of transgenic plants was enhanced after application of 5-azacytidine. The presence of integrated T-DNA was checked by PCR and confirmed by Southern hybridization. T-DNA was stably transmitted to the next generation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009679908948
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  • 22
    Electronic Resource
    Electronic Resource
    Field resistance to Tomato spotted wilt virus in transgenic peanut (Arachis hypogaea L.) expressing an antisense nucleocapsid gene sequence (2000)
    Springer
    Molecular breeding 6 (2000), S. 227-236 
    Details
    ISSN: 1572-9788
    Keywords: antisense DNA ; co-transformation ; nucleocapsid gene ; pathogen-derived resistance ; somatic embryogenesis ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Peanut (Arachis hypogaea L.) lines transgenic for the antisense nucleocapsid (N) gene of a Tomato spotted wilt virus (TSWV) strain isolated from peanut were generated by microprojectile-mediated transformation of repetitive somatic embryos of cultivars VC1 and AT120. The selectable marker (hygromycin resistance) and the N gene were on separate plasmids. A total of 207 VC1 and 120 AT120 hygromycin-resistant lines were produced. Of all the VC1 plants recovered 71% were cotransformed with the N gene (N+), but all plants were sterile. For AT120, 48 of the transgenic cell lines converted into plants. Polymerase chain reaction (PCR) screening showed 15 of the lines were transgenic for the N gene (N+), and two of these lines were fertile. A field test was conducted in 1998 at Ashburn, GA, using seeds from each fertile line, along with segregated and non-transgenic controls. Plants from four randomly selected field plots were examined for symptoms and analyzed by double-antibody sandwich enzyme-linked immunoabsorbent assay and PCR at 10 and 14 weeks after planting. At 14 weeks, 76% of the N+ plants were symptomless, while 2% were severely symptomatic or dead. In contrast, only 42% of the plants lacking the N gene were symptomless and 50% were severely symptomatic or dead. Northern blot analysis of selected field-resistant plants detected transgene RNA, and the transcript level appeared undiminished after viral exposure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009649408157
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  • 23
    Electronic Resource
    Electronic Resource
    Insect- and herbicide-resistant transgenic eucalypts* (2000)
    Springer
    Molecular breeding 6 (2000), S. 307-315 
    Details
    ISSN: 1572-9788
    Keywords: bar ; cry3A ; Eucalyptus ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Transgenic Eucalyptus camaldulensis containing both the insecticidal cry3A gene and the bar gene (conferring tolerance to the herbicide glufosinate ammonium) have been produced by Agrobacterium tumefaciens-mediated transformation of seedling explants. Transgenic plants from two lines tested were resistant to first instars of chrysomelid beetles that are important pests of commercial Australian eucalypt plantations. Both lines also exhibit tolerance to the broad-spectrum herbicide Liberty® at 6 l/ha (1.2 kg active ingredient per hectare), twice the field application rate. Transgenic insect- and herbicide-resistant eucalypts like these are likely to provide better insect and weed control options in plantations, particularly during the vulnerable establishment phase, provided that any adverse ecological impacts of releasing transgenic trees into the environment can be assessed and minimized.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009676214328
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  • 24
    Electronic Resource
    Electronic Resource
    Transformation of Japanese persimmon (Diospyros kaki Thunb.) with a bacterial gene for choline oxidase (2000)
    Springer
    Molecular breeding 6 (2000), S. 501-510 
    Details
    ISSN: 1572-9788
    Keywords: choline oxidase ; glycinebetaine ; Japanese persimmon ; salt tolerance ; transformation ; woody plant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This report describes the first successful genetic engineering of tolerance to salt in an agriculturally important species of woody plants by Agrobacterium-mediated transformation with the codA gene of Arthrobacter globiformis. This gene encodes choline oxidase, which catalyzes the oxidation of choline to glycinebetaine. The binary plasmid vector pGC95.091, containing a kanamycin-resistance gene (nptII), a gene for β-glucuronidase (gusA) and the codA gene in its T-DNA region, was used with a disarmed strain of Agrobacterium tumefaciens, EHA101, to transform Japanese persimmon (Diospyros kaki Thunb. `Jiro') by the leaf disk transformation method. The pRS95.101 plasmid that included only nptII and gusA in the T-DNA region was used as a control. We selected eight transgenic lines with one or two copies of the T-DNA after transformation with pGC95.091 (PC lines) and three lines after transformation with pRS95.101 (PR lines). The eight PC lines produced choline oxidase and glycinebetaine whereas neither was found in untransformed `Jiro' and in the control PR lines. Transgenic plants grew normally, resembling wild-type plants both in vitro and ex vitro. The activity of photosystem II in leaves of the transgenic Japanese persimmon plants under NaCl stress was determined in terms of the ratio of the variable (F v) to the maximum (F m) fluorescence of chlorophyll (F v/F m). The rate of decline in (F v/F m under NaCl stress was lower in the PC lines than in the control PR lines. These results demonstrated that genetic engineering of Japanese persimmon, which allowed it to accumulate glycinebetaine, enhanced the tolerance to salt stress of this plant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026513831290
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  • 25
    Electronic Resource
    Electronic Resource
    Generation of transgenic wheat (Triticum aestivum L.) for constitutive accumulation of an Aspergillus phytase (2000)
    Springer
    Molecular breeding 6 (2000), S. 195-206 
    Details
    ISSN: 1572-9788
    Keywords: heterologous protein accumulation ; phytate phosphorus digestibility ; phytase ; phytic acid ; transformation ; Triticum aestivum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The Aspergillus niger phytase-encoding gene (phyA) has been constitutively expressed in wheat. Transgenic wheat lines were generated by microprojectile bombardment of immature embryos, using the bar-Bialaphos selection system. The bar and the phyA gene expression were controlled by the maize ubiquitin-1 promoter. To ensure secretion and glycosylation of the microbial phytase, an expression cassette was designed (Ubi-SP-Phy) where an α-amylase signal peptide sequence was inserted between the promoter and the phytase coding region. A similar cassette was constructed without the signal peptide sequence (Ubi-Phy). Five lines of fertile wheat transformed with the Ubi-SP-Phy were generated and two lines with the Ubi-Phy construct. The inheritance of the phyA gene was monitored through three generations. Western blotting of leaf and seed derived protein revealed the presence of an immunoreacting polypeptide of the size expected for the Aspergillus phytase. Up to 25 days after pollination, the heterologous phytase was exclusively present in the pericarp-seed coat-aleurone fraction. Thereafter, it accumulated in the endosperm in amounts exceeding that found in the seed coat and aleurone. The phyA mRNA and derived protein could at no stage be detected in the embryo. The Ubi-SP-Phy transgenic seeds exhibited up to 4-fold increase of phytase activity while up to 56% increase was found in Ubi-Phy plants. It is concluded that a functional Aspergillus phytase can be produced in significant amounts in wheat grains. This may be of relevance for improving the phytate-phosphorus digestibility when wheat grains are used for non-ruminant animal feed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009690730620
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  • 26
    Electronic Resource
    Electronic Resource
    Transformation of Brassica juncea (L.) Czern with bacterial codA gene enhances its tolerance to salt stress (2000)
    Springer
    Molecular breeding 6 (2000), S. 489-499 
    Details
    ISSN: 1572-9788
    Keywords: Choline oxidase ; glycinebetaine ; transformation ; Brassica juncea ; salt stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The codA gene for biosynthesis of glycinebetaine from Arthrobacter globiformis was used for transforming Brassica juncea cv. Pusa Jaikisan (which lack any means to synthesize glycinebetaine) through Agrobacterium mediated transformation. The stable insertion of the codA gene in the shoots obtained on medium with kanamycin and hygromycin was confirmed by PCR analysis of the nptII gene. Southern hybridization with a codA probe further demonstrated its successful integration. Immunoblot analysis revealed the presence of choline oxidase demonstrating that the bacterial codA gene had been successfully transcribed and translated. The seeds of transgenic lines showed enhanced capacity to germinate under salt stress as compared to that of the wild type. Further, the seedlings of transgenic plants that expressed codA gene showed significantly higher growth than that of the wild type under salt stress conditions. These results demonstrated that the introduction of a biosynthetic pathway for glycinebetaine into Brassica juncea significantly enhanced their salt tolerance. Hence, homozygous genotypes of selected transformed lines can be exploited for improving the salt tolerance of the desirable cultivars of Brassica juncea through breeding programmes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026542109965
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  • 27
    Electronic Resource
    Electronic Resource
    Transforming Self and Society: A "Critical Appreciation" Model (2000)
    Springer
    Systemic practice and action research 13 (2000), S. 475-501 
    Details
    ISSN: 1573-9295
    Keywords: reflection ; transformation ; self-society dynamics ; critical systems thinking ; systemic intervention ; critical self-reflection ; ideology-critique ; critical appreciation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Sociology
    Notes: Abstract This paper sets out to uncover some relationships between reflection, discourse and action. By challenging and synthesizing some polemical arguments concerning the creation, maintenance, and transformation of self and society, a model of self-society dynamics that operates through reflection, discourse, and action is developed. The model of self-society dynamics brings together aspects of self-reflection and ideology-critique (explored in the paper), which it is suggested are required for any intervention (transformative action) to be grounded in locally meaningful ways. By creating a dialog community in which self- and group assumptions can be subjected to validation through discourse, it is proposed that a dynamic balance between individual needs and broader societal aims may be achieved. If individuals can be open to such discourse (i.e., they can become critically self-reflective), then it is argued that possibilities for achieving sustainable change will be significantly enhanced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009541430809
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  • 28
    Electronic Resource
    Electronic Resource
    Is Multidimensional High Performance Liquid Chromatography (HPLC) an Alternative in Protein Analysis to 2D Gel Electrophoresis? (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 259-265 
    Details
    ISSN: 0935-6304
    Keywords: Proteomics ; protein analysis ; multidimensional HPLC ; ion-exchange chromatography ; reversed phase chromatography ; comprehensive HPLC ; two-dimensional HPLC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The interactive modes of High Performance Liquid Chromatography (HPLC) of proteins provide a platform for the construction of a multidimensional HPLC system coupled to mass spectrometry. We present a system composed of both anion and cation exchanger columns, in the first dimension, and n-octadecyl bonded 1.5 μm nonporous silica columns in the second dimension. Both columns are operated under gradient conditions. A system suitability test with standard proteins showed that the total analysis can be performed within about 20 minutes. The fractions taken from the ion exchanger column are directly analyzed within one minute on the reversed phase column at a high flow rate. Two reversed phase columns are applied and operated alternatively: while the first column performs the separation within one minute, the analytes leaving the first dimension are enriched in an on-column focusing mode on top of the second column. The sample clean-up and enrichment is performed on a novel type of restricted access cation exchanger column with internal sulfonic acid groups and external diol groups. The columns exhibit a molecular weight exclusion limit for globular proteins of about 15 kDa. Our next studies will be directed towards the analysis of proteins and peptides from extracts of fibroblasts.
    Additional Material: 4 Ill.
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  • 29
    Electronic Resource
    Electronic Resource
    Potential of Flame Ionization Detection Coupled On-Line with Microcolumn Liquid Chromatography Using Aqueous Eluents and an Eluent-Jet Interface (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 309-316 
    Details
    ISSN: 0935-6304
    Keywords: μLC ; FID ; LC-FID ; carbohydrates ; amino acids ; alcohols ; phosphonic acids ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The potential of the on-line coupling of microcolumn liquid chromatography (μLC) using aqueous eluents with a flame ionization detector (FID) was evaluated. An eluent-jet interface was modified to allow the efficient introduction of the eluent into the FID. The potential of the method is demonstrated by the μLC-FID determination of lower alcohols and bis(2-hydroxyethylthio)alkanes on porous and non-porous stationary phases, respectively. Flow injection analysis (FIA)-FID experiments with highly polar, thermolabile, semi-volatile and non-volatile compounds like amino acids, organic acids, alkylphosphonic acids, and carbohydrates showed the developed configuration to be a promising approach for the detection of a wide range of analytes. Compared with a nebulization interface, the eluent-jet interface showed 4-10 times higher peaks for citric acid. Detection limits by FIA for all compounds were in the range of 0.2-5 ng injected. With ribose as test compound, plots of peak height vs. amount injected showed good linearity (r2 〉 0.999) in the range of 75-12,000 μg/mL. The repeatability showed relative standard deviations of less than 5%.
    Additional Material: 7 Ill.
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  • 30
    Electronic Resource
    Electronic Resource
    Seed Oil Fatty Acids of Mongolian Compositae: The trans-Fatty Acids of Heteropappus hispidus, Asterothamnus centrali-asiaticus and Artemisia palustris (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 360-366 
    Details
    ISSN: 0935-6304
    Keywords: Artemisia palustris ; Asterothamnus centrali-asiaticus ; capillary gas liquid chromatography ; Compositae (Asteraceae) ; Heteropappus hispidus ; seed oil ; silver ion thin layer chromatography ; trans-fatty acids ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Seed oils from the Compositae plant family are known to contain a variety of unusual fatty acids. Subsequent to the recent discovery of γ-linolenic acid in Saussurea and Youngia, further Mongolian Compositae species were investigated for their seed oil fatty acid composition. A number of δ3trans-fatty acids (16 : 1δ3t, 18 : 1δ3t and 18 : 3δ3t, 9c, 12c) were found in the seed oils of Heteropappus hispidus and Asterothamnus centrali-asiaticus. The latter fatty acid, but not the trans-monoenes, was also found in one species of Artemisia. These unusual fatty acid isomers were characterized by capillary gas-liquid chromatographic (GLC) separations in combination with other chromatographic techniques (analytical thin layer chromatography, TLC and preparative argentation TLC), and infrared spectrocsopy (IR). Their identity was further confirmed by co-chromatography with other seed oils known to contain these trans-fatty acids. The fact that within the Compositae plant family there are apparently two or three distinct groups of genera containing δ3trans-fatty acids is discussed.
    Additional Material: 5 Ill.
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  • 31
    Electronic Resource
    Electronic Resource
    Supercritical Fluid Sample Introduction of Unstable Organometallic Compounds in Supercritical Fluid Chromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 386-388 
    Details
    ISSN: 0935-6304
    Keywords: On-line SFE-SFC ; organometallics ; purity testing ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 32
    Electronic Resource
    Electronic Resource
    Supercritical Fluid Extraction of Euphorbia rigida (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 397-400 
    Details
    ISSN: 0935-6304
    Keywords: Supercritical fluid extraction ; capillary GC ; hydrocarbons ; bio-oil ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 33
    Electronic Resource
    Electronic Resource
    Comparison of Three Sorbents for Clean-Up of Mixed Aliphatic Hydrocarbons, PCBs, and PCTs Prior to Simultaneous Determination by GC-ECD/FID (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 401-404 
    Details
    ISSN: 0935-6304
    Keywords: Clean-up ; aliphatic hydrocarbons ; organochlorine compounds ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 34
    Electronic Resource
    Electronic Resource
    Simultaneous Speciation Analysis of Fe(II) and Fe(III) in Mineral Samples by Using Capillary Electrophoresis (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 430-436 
    Details
    ISSN: 0935-6304
    Keywords: Speciation ; digestion ; capillary electrophoresis ; ferrous ; ferric ; mineral analysis ; complexation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Capillary electrophoresis is used as a means of cation separation for cationic speciation analysis. Acceptable separation of ferrous and ferric iron was achieved by using a mixed complexing agent run buffer which gave stable species in solution. These iron species, and total iron, were determined simultaneously in certified reference materials with a single digestion step. A variety of digestion techniques were compared, primarily for their non-oxidative capabilities in order to preserve the oxidation state of iron in the mineral samples. The most favorable recoveries resulted from a continuous flow nitrogen purge technique. Total iron levels obtained from the CE method were compared with those determined by two spectroscopic techniques, with similar results obtained using the different instrumental methods.
    Additional Material: 3 Ill.
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  • 35
    Electronic Resource
    Electronic Resource
    Separation of Enantiomers of Drugs by Capillary Electrophoresis with Permethyl-gamma-Cyclodextrin as Chiral Solvating Agent (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 413-429 
    Details
    ISSN: 0935-6304
    Keywords: Capillary electrophoresis ; enantiomer separation ; chiral drugs ; TM-γ-cyclodextrin ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---High-throughput screening is a promising new approach in analytical chemistry. Within the framework of an extended screening program (The German-Chinese Drug Screening Program), the enantioseparation of 86 drugs was investigated by capillary zone electrophoresis in the presence of the chiral solvating agent (CSA) octakis-(2,3,6-tri-O-methyl)-γ-cyclodextrin (TM-γ-CD). By this means, 15 drugs could be separated into enantiomeric pairs. Approximate measures for the degree of interaction (migration retardation factor, Rm) and for the degree of enantiomer recognition (migration separation factors, αm) revealed intriguing patterns that were compared with those found for native γ-cyclodextrin (γ-CD). Although there is a distinct influence of the analyte structure on the electrophoretic data, interpretation remains difficult. Most remarkably, permethylation of γ-CD leads neither to a higher affinity nor to better chiral recognition, in contrast to the findings with α-CD.
    Additional Material: 10 Ill.
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  • 36
    Electronic Resource
    Electronic Resource
    Retention Prediction System of O-Aryl,O-(1-methylthioethylidene-amino)phosphates on RP-HPLC (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 445-448 
    Details
    ISSN: 0935-6304
    Keywords: O-Aryl,O-(1-methylthioethylideneamino)phosphates ; retention prediction ; quantitative structure-retention relationship (QSRR) ; reversed-phase HPLC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Using factor analysis and stepwise linear regression methods, two parameters - CMR and ECCR - were selected from eight solute-related structure parameters as the most retention-influencing parameters. The relationships between the retention data (k ´) and the two structure parameters were established for 13 O-aryl,O-(1-methylthioethylideneamino)phosphate compounds under a wide range of experimental conditions. The retention data (k ´) of another seven compounds with similar structures were predicted using these QSRR equations. Good agreement was obtained between the experimental k ´ values and predicted ones.
    Additional Material: 1 Ill.
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  • 37
    Electronic Resource
    Electronic Resource
    Temperature-Programmed Packed Capillary Liquid Chromatography Coupled to Fourier-Transform Infrared Spectroscopy (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 525-530 
    Details
    ISSN: 0935-6304
    Keywords: Packed capillary liquid chromatography ; temperature programming ; Fourier-transform infrared spectroscopy ; polymer additives ; pneumatic nebulization ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Temperature-programmed packed capillary liquid chromatography has been coupled off-line to Fourier-transform infrared spectroscopy, utilizing a commercially available interface with a pneumatic nebulizer rebuilt to handle low flow rates at elevated temperatures. The modified interface showed excellent performance with regard to non-aqueous reversed phase separations of polymer additives, resulting in constructed Gram-Schmidt chromatograms comparable to chromatograms obtained using UV detection. The spray of the in-house constructed nebulizer was not influenced by temperature changes of the column effluent, and hence temperature-programmed gradient separations could be used successfully. The relative standard deviation of peak height was 4.4% (n = 5) and the mass limit of detection was determined to be about 40 ng, using a polymer antioxidant as model compound. The present instrumental coupling has been used for characterization of the antioxidant Irgafos P-EPQ.
    Additional Material: 5 Ill.
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  • 38
    Electronic Resource
    Electronic Resource
    Separation of Enantiomers by On-Line Capillary Isotachophoresis-Capillary Zone Electrophoresis (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 531-538 
    Details
    ISSN: 0935-6304
    Keywords: Capillary isotachophoresis ; capillary electrophoresis ; column-coupling electrophoresis ; enantiomers ; chiral ; amino acids ; tryptophan ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The ability of capillary zone electrophoresis (CZE) coupled on-line with capillary isotachophoresis (ITP) sample pretreatment in the column-coupling capillary electrophoresis equipment to separate trace enantiomers present in samples of complex ionic matrices and enantiomers present in their mixtures at significantly differing concentrations has been studied. Enantiomers of 2,4-dinitrophenyl labeled norleucine (DNP-Nleu) and tryptophan enantiomers were employed as model analytes in this work while urine and mixtures of tryptophan enantiomers of differing concentrations served as model samples. Experiments performed with urine samples spiked with the DNP-Nleu racemate at sub-μmol/L concentrations demonstrated excellent sample pretreatment capabilities of ITP (concentration of the analytes, in-column and post-column sample clean up) when coupled on-line with chiral CZE separations. In the CZE separations of enantiomers present in the samples at trace concentrations the sample pretreatment could be performed in both achiral and chiral ITP electrolyte systems. The use of a chiral electrolyte system was found to be essential in the ITP pretreatment of the samples containing the enantiomers at very differing concentrations. For example, a 2×10-7 mol/L concentration of L-tryptophan could be detected in the CZE separation stage of the ITP-CZE combination in samples containing about a 104 excess of D-tryptophan only when the ITP pretreatment was carried out in the electrolyte system providing the resolution of enantiomers (α-cyclodextrin served for this purpose in the present work). A post-column ITP sample clean up was found effective in enhancing the destacking rate of the trace enantiomer in the CZE stage when the migration configuration of the enantiomers was less favorable (the trace constituent migrating behind the major enantiomer).
    Additional Material: 8 Ill.
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  • 39
    Electronic Resource
    Electronic Resource
    Characterization and Comparison of Tea Tree and Lavender Oils by Using Comprehensive Gas Chromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 554-560 
    Details
    ISSN: 0935-6304
    Keywords: Comprehensive gas chromatography ; multidimensional gas chromatography ; essential oils ; coupled column analysis ; high resolution analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The essential oils from French lavender (Lavandula angustifolia) and tea tree (Melaleuca alternifolia) were separated by the two-dimensional GC technique of comprehensive gas chromatography. A coupled column combination of non-polar (5% phenyl equivalent) and polyethylene glycol phase columns was used to provide the desired resolution performance. By using a range of known standards, some of the peaks in lavender oil can be assigned. Some of these also occur in tea tree oil; however, from our knowledge of the major constituents in this oil and their relative retention behaviour, most of the major peaks may be tentatively assigned within the 2-dimensional separation space. There appear to be elution patterns within the 2-D space which should be useful in correlating retention with chemical and structural properties of the components, although this will require further evaluation. A range of coeluting peaks, which may not be so readily separated by using a single column capillary GC analysis, are resolved in the experiment described.
    Additional Material: 10 Ill.
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  • 40
    Electronic Resource
    Electronic Resource
    Liquid Chromatography of Unstable Zinc Dithiocarbamates. Application to Rubber Gloves Analysis (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 565-566 
    Details
    ISSN: 0935-6304
    Keywords: Liquid chromatography ; zinc dithiocarbamate ; vulcanization accelerator ; rubber gloves ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 41
    Electronic Resource
    Electronic Resource
    Characteristic Stationary Phase Constants for Two Popular Open-Tubular Column Stationary Phases for Gas Chromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 603-608 
    Details
    ISSN: 0935-6304
    Keywords: Solvation parameter model ; ystem constants for poly(dimethyldiphenylsiloxane) HP-5 and poly(ethylene glycol) HP-INNOWax stationary phases ; temperature ; molecular interaction ; retention models ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 42
    Electronic Resource
    Electronic Resource
    Gas Chromatographic Enantiomer Separation of Atropisomeric PCBs Using Modified Cyclodextrins as Chiral Phases (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 619-627 
    Details
    ISSN: 0935-6304
    Keywords: Enantiomer separation ; mixed chiral selectors ; modified cyclodextrins ; gas chromatography ; PCB ; o,p´-DDD ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Columns containing different types of cyclodextrin derivatives have been evaluated for chiral gas chromatographic separation of atropisomeric PCBs, o,p´-DDT and o,p´-DDD. Separation was attempted on columns containing mixed chiral selectors, and the performance of two closely related selectors was also examined. The cyclodextrins were: permethylated-β-CD (PM-β-CD), heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-β-CD (2,3-M-6-TBDMS-β-CD), heptakis(2,3-di-O-methyl-6-O-tert-hexyldimethylsilyl)-β-CD (2,3-M-6-THDMS-β-CD), and heptakis(2,3-di-O-ethyl-6-O-tert-hexyldimethylsilyl)-β-cyclodextrin (2,3-E-6-THDMS-β-CD). The cyclodextrins were dissolved in OV-1701 or in a dimethylsiloxane/silarylene copolymer containing 5% phenyl in the backbone. The application of mixed chiral selectors led to improved separations, however; at most eleven PCB congeners were separated on a single column. Chiral resolution of o,p´-DDD was achieved. The use of a dimethylsiloxane/silarylene copolymer as a matrix for the cyclodextrins is a promising approach. With such a matrix, blocking of the CD cavities by silicone substituent groups can be avoided, and a reasonable CD solubility can be provided. The selectivity of heptakis(2,3-di-O-ethyl-6-O-tert-hexyldimethylsilyl)-β-CD and heptakis(2,3-di-O-methyl-6-O-tert-hexyldimethylsilyl)-β-CD was quite different, the former selector could separate four congeners, while the latter separated ten congeners.
    Additional Material: 5 Ill.
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  • 43
    Electronic Resource
    Electronic Resource
    Simultaneous Determination of Organic Acids in Wine Samples by Capillary Electrophoresis and UV Detection: Optimization with Five Different Background Electrolytes (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 647-652 
    Details
    ISSN: 0935-6304
    Keywords: Capillary electrophoresis ; UV detection ; organic acids ; background electrolyte optimization ; wine ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A simple technique is described for the routine capillary electrophoretic determination of organic acids in wine samples. Several aromatic and non-aromatic compounds, including phthalic acid, benzoic acid, sorbic acid, boric acid, and phosphate, were evaluated as background electrolytes in order to obtain the highest resolution and detection sensivity. Factors that affect capillary electrophoretic separation such as the concentration and pH of the background electrolyte (BGE), the concentration of the electroosmotic flow modifier (EOF), and methanol addition to the electrolyte were investigated systematically. Tartaric, malic, succinic, acetic, and lactic acids were determined simultaneously in approximately six minutes using an electrolyte containing 3 mM phosphate and 0.5 mM myristyltrimethylammonium bromide (MTAB) as electroosmotic flow modifier at pH 6.5. This method is quantitative, with recoveries in the 90-102% range and linear up to 50 mg L-1. The precision is better than 1% and the procedure shows the appropriate sensibility, with detection limits between 0.015 and 0.054 mg L-1. The proposed method was successfully employed for the determination of organic acids in wine samples by direct sample injection after appropriate dilution and filtration.
    Additional Material: 5 Ill.
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  • 44
    Electronic Resource
    Electronic Resource
    Regenerable MnO-based Glass Absorber Tube with Press-Fit Connection for Easy Post-Injector Evaluation of Carrier Gases Oxygen Contamination (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 688-692 
    Details
    ISSN: 0935-6304
    Keywords: Solid oxygen scavenger ; carrier gas purity ; manganous oxide ; glass press-fit connections ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 6 Ill.
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  • 45
    Electronic Resource
    Electronic Resource
    Determination of Free D-Amino Acids in Mammalia by Chiral Gas Chromatography-Mass Spectrometry (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 576-582 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography-mass spectrometry ; amino acid enantiomers ; D-amino acids ; physiological fluids ; mammals ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Quantities of D-amino acids were determined in body fluids (urine, blood plasma and blood serum, milk) of mammals (hamster, horse, bovine, sheep, pig, and dog). Amino acids were isolated using a cation exchanger and converted into their N(O)-pentafluoropropionyl (or trifluoroacetyl) amino acid 2-propyl esters. Enantiomers were separated and quantified on a Chirasil-L-Val capillary column with mass spectrometric detection using selected ion monitoring. D-Enantiomers of most protein L-amino acids were detected. Largest absolute and relative amounts in most cases were determined for D-Ser and D-Ala in urine. Stereoisomers of 2,6-diaminopimelic acid were also measured in bovine, ovine, and porcine urine. Since D-amino acids were detected in all representative classes of the major orders of Mammalia, namely Artiodactyla, Perissodactyla, Rodentia, and Carnivora, and taking reports in the literature into account, it is postulated that D-amino acids occur in all mammals.
    Additional Material: 5 Ill.
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  • 46
    Electronic Resource
    Electronic Resource
    Optimization of a GC-MS/MS Method for the Analysis of PCDDs and PCDFs in Human and Fish Tissue (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 595-599 
    Details
    ISSN: 0935-6304
    Keywords: GC-MS/MS ; PCDDs ; PCDFs ; human tissue ; fish tissue ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---This paper outlines the possibilities of selectivity and sensitivity enhancement in measuring PCDD/F congeners using an ion trap GC-MS/MS. The pressure of the collision gas and the collision energy were optimized. The modified GC-MS/MS method was applied to the determination of PCDDs and PCDFs in human and fish tissues. Limits of quantification were about 1 pg/g of fat for all seventeen 2378 PCDD/Fs tested (starting amount of fat, 2 g).
    Additional Material: 2 Ill.
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  • 47
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    Electronic Resource
    Use of Coupled HPLC/1H NMR and HPLC/ESI-MS for the Detection and Identification of (2E,4Z)-Decadienoic Acid from a New Agromyces Species (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 609-612 
    Details
    ISSN: 0935-6304
    Keywords: On-line coupling HPLC/NMR ; HPLC/ESI-MS ; (2E,4Z)-decadienoic acid ; Agromyces spec ; isolation ; structure elucidation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 4 Ill.
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  • 48
    Electronic Resource
    Electronic Resource
    Direct High-Performance Liquid Chromatographic Enantioseparation of β-Methyl-Substituted Unusual Amino Acids on a Quinine-Derived Chiral Anion-Exchange Stationary Phase (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 628-636 
    Details
    ISSN: 0935-6304
    Keywords: High-performance liquid chromatography ; β-methyl amino acids ; enantioseparation ; quinine-derived chiral stationary phase ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A quinine-derived chiral anion-exchange stationary phase was used for the direct high-performance liquid chromatographic separation of the enantiomers of the N-protected unusual β-substituted α-amino acids, β-methylphenylalanine, β-methyltyrosine, β-methyltryptophan, and β-methyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid. The readily prepared 2,4-dinitrophenyl and tert-butyloxycarbonyl derivatives were well separated, and in most cases the separation of all four stereoisomers of these β-methyl-α-amino acids could be obtained in one chromatographic run. The elution sequences of the enantiomers of the different derivatives were determined and revealed a dependence on the type of the N-protecting group. In this context, the effects of different protecting groups (acetyl, tert-butyloxycarbonyl, benzoyl, 3,5-dinitrobenzoyl, benzyloxycarbonyl, 3,5-dinitrobenzyloxycarbonyl, 2,4-dinitrophenyl, and 9-fluorenylmethoxycarbonyl) on the chromatographic behavior were investigated.
    Additional Material: 6 Ill.
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  • 49
    Electronic Resource
    Electronic Resource
    Optimization and Validation of a Fast Liquid Gradient for Determination of Prominent Flavan-3-ols and Flavonols in Fresh Vegetables (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 637-643 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; fast separation ; flavan-3-ol ; flavonols ; vegetables ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A fast high-performance liquid chromatography method was used for analysis of prominent flavan-3-ols and flavonols in vegetables. Gradient elution with phosphoric acid-acetonitrile mixtures and phosphoric acid-methanol mixtures allowed fast and complete separation of the studied phenolic compounds within analysis times less than 10 min. The development of two elution gradients using methanol and acetonitrile as modifiers proved to be an excellent approach for the verification of the real polyphenolic composition in vegetables samples because the two optimized methods allowed the separation of the same number of compounds in the same elution order. Diode-array detection was employed for the provisional identification of phenolic compounds that were not available as standards. We preferred methanol as a modifier because it was less toxic and cheaper than acetonitrile. Detection limits ranged between 0.12 and 0.59 μg mL-1. High recoveries of phenolics from fresh vegetables were measured in all studied cases, independent of the phenolic structure, matrix, and vegetable in question. High levels of procyanidins between 150 and 450 mg kg-1 were found in all studied vegetables. Quantification of quercetin and kaempferol glycosides was only possible in marrow and onion, respectively.
    Additional Material: 3 Ill.
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  • 50
    Electronic Resource
    Electronic Resource
    Characterization of Inulins by Capillary Electrophoresis with Laser Induced Fluorescence Detection (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 656-658 
    Details
    ISSN: 0935-6304
    Keywords: Capillary electrophoresis (CE) ; laser induced fluorescence detection (LIFD) ; fluorescein isothiocyanate (FITC) ; inulin ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 51
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    Electronic Resource
    Determination of Scoparone in Citrus Roots by Micellar Electrokinetic Capillary Chromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 519-521 
    Details
    ISSN: 0935-6304
    Keywords: Scoparone ; phytoalexin ; citrus ; MEKC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A new MEKC method has been developed to determine the amount of the phytoalexin, scoparone, in Citrus roots. The separation and analysis was achieved with a running buffer of 100 mM SDS, 25 mM phosphate and 12% (v/v) methanol pH 6.2. Separation was performed at 12 kV with 25°C and UV detection at 200 nm. A near complete recovery of scoparone was obtained with the extraction procedure. The MEKC method was compared with a fluorescence TLC method. The detection limit for scoparone with the MEKC method (2 μg/mL) was better than the TLC method (10 μg/mL).
    Additional Material: 2 Ill.
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  • 52
    Electronic Resource
    Electronic Resource
    Determination of Pollutant Phenols by Capillary High-Performance Liquid Chromatography with UV Detection (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 367-372 
    Details
    ISSN: 0935-6304
    Keywords: Capillary HPLC ; gradient elution ; temperature programming ; phenolic compounds ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---This paper describes a liquid chromatographic method using a reversed phase capillary column coupled to an UV detector for the quantitation of thirteen pollutant phenols. Chromatographic separation was carried out with gradient elution at 25.0 ± 0.1°C. The two major anisocratic elution modes (gradient elution and temperature programming) were evaluated. The detection limit range was 10-81 pg (100 nL injected). The chromatographic method combined with liquid-liquid extraction was applied to analysis of these compounds in river water. Recoveries of 75-103% were achieved for most of them.
    Additional Material: 5 Ill.
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  • 53
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    Electronic Resource
    Separation and Determination of Phenolic Antioxidants by HPLC with Surfactant/n-Propanol Mobile Phases (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 324-328 
    Details
    ISSN: 0935-6304
    Keywords: Antioxidants ; propyl gallate ; octyl gallate ; dodecyl gallate ; butylated hydroxyanisole ; butylated hydroxytoluene ; reverse-phase liquid chromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The influence of cationic and anionic surfactants and short-chain alcohols in the mobile phase on the retention of five antioxidants has been studied. The solutes chosen were butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and propyl, octyl, and dodecyl gallates (PG, OG, DG).The surfactants were hexadecyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), and n-propanol (PrOH) was the selected alcohol. A simple isocratic reversed-phase method for the antioxidant determination is proposed. Separation of five primary antioxidants takes 18 min with the mobile phase SDS 0.10 M/H3PO4 0.01 M/PrOH 30%. Variation of the percentage of alcohol in the mobile phase permits optimization of the retention times of the antioxidants. Detection limits in the pg range were obtained for the all solutes. The method was used to determine the antioxidants in olive oil at three different levels, giving mean recoveries close to 100% for all the solutes (BHA 102%, PG 99%, OG 99%, DG 99%) except BHT (84%).
    Additional Material: 3 Ill.
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  • 54
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    Electronic Resource
    Analysis of Polyunsaturated Fatty Acids Using High Performance Liquid Chromatography - Atmospheric Pressure Chemical Ionization Mass Spectrometry (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 338-342 
    Details
    ISSN: 0935-6304
    Keywords: Polyunsaturated fatty acids (PUFA) ; high performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (LC-MS with APCI) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Analysis of polyunsaturated fatty acids using high performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry is described. The standard fatty acid methyl esters from 16 to 22 carbons were analyzed by LC-MS with APCI. The effect of orifice voltage and total carbon atoms versus number of double bonds in each homologue on the mass spectra is discussed. The correction coefficients for homologues from saturated fatty acids to hexaenoic acid are also mentioned.
    Additional Material: 4 Ill.
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  • 55
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    Electronic Resource
    2H/1H Ratio Analysis of Flavor Compounds by On-Line Gas Chromatography Pyrolysis Isotope Ratio Mass Spectrometry (HRGC-P-IRMS): Benzaldehyde (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 357-359 
    Details
    ISSN: 0935-6304
    Keywords: 2H/1H ratio analysis ; HRGC-P-IRMS ; stable isotopes ; benzaldehyde ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Isotope ratio monitoring gas chromatography-mass spectrometry of the 2H/1H ratio by pyrolysis isotope ratio mass spectrometry (P-IRMS) was used to analyze benzaldehyde originating from various sources. Based on the δ2HSMOW value of an authentic reference sample determined with an elemental analyzer (EA), the range of reproducibility and linearity was checked. Correct (EA related) and reproducible data were obtained for sample amounts 〉0.6 μg benzaldehyde (on column). In another series of experiments, the influence of sample preparation, i. e. simultaneous distillation-extraction (SDE) was found to be negligible. The following ranges of δ2HSMOW values were determined for benzaldehyde using five types of samples, i. e. (i) synthetic (δ2HSMOW -78 to -85‰, ex benzal chloride; +420 to +668‰, ex toluene) and ‘natural’ (including ‘ex-cassia’) references (δ2HSMOW -83 to -144‰); (ii) bitter almond oils (δ2HSMOW -113 to -148‰); (iii) fruits (δ2HSMOW -111 to -146‰); (iv) kernels (δ2HSMOW -115 to -188‰); and (v) leaves (δ2HSMOW -165 to -189‰).
    Additional Material: 1 Ill.
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  • 56
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    Electronic Resource
    Effects of Injected Volume and Applied Voltage on Column Efficiency in Capillary Electrochromatography with Open Tubular Columns of 10 μm i. d. (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 373-378 
    Details
    ISSN: 0935-6304
    Keywords: Open tubular columns ; capillary electrochromatography ; column efficiency ; injected volume ; applied voltage ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of some instrumental parameters on column efficiency in open tubular capillary electrochromatography (OTCEC) has been evaluated. First, it was investigated whether band broadening due to the sample injection process is within a tolerable range when an open tubular column (OTC) of about 10 μm i. d. is used. As a result of the small injection profile factor (K2 = 1.3), injected volumes must be sufficiently small (less than 10 pL) to avoid a significant efficiency loss (〉5%) when hydrodynamic injection by siphoning is employed. Secondly, the kinetic performance of OTCs in a CEC system was estimated from the variation of the reduced plate height (h) with the reduced linear velocity (ν) which was controlled by the voltage applied. Reasonable agreement was obtained between the theoretical h versus ν curve and the experimental values for a group of polycyclic aromatic hydrocarbons used as test compounds. Values of 0.25 for minimum h at an optimum ν of 16 are estimated, which permit separations with around 400,000 plates per meter to be obtained in less than 5 min. Finally, the possibility of estimating the diffusion coefficients of the solutes in the mobile phase from the plot of the height of a theoretical plate versus electroosmotic flow velocity is shown.
    Additional Material: 5 Ill.
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  • 57
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    Electronic Resource
    Use of Capillary Supercritical Fluid Chromatography in the Analysis of Zinc Dialkyldithiophosphates (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 389-392 
    Details
    ISSN: 0935-6304
    Keywords: Capillary SFC ; zinc dialkyldithiophosphates ; lubricating oils ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 58
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    Electronic Resource
    Application of Supercritical Fluid Chromatography to the Analysis of Waxes in Objects of Art (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 393-396 
    Details
    ISSN: 0935-6304
    Keywords: Supercritical fluid chromatography (SFC) ; micropacked capillary columns ; waxes ; restoring ; objects of art ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 59
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    Identification of Free and Glycosidically Bound Volatiles and Glycosides by Capillary GC and Capillary GC-MS in “Lulo del Chocó” (Solanum topiro) (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 379-385 
    Details
    ISSN: 0935-6304
    Keywords: Aroma ; “lulo del Chocó” ; Solanum topiro ; volatiles ; glycosidically bound volatiles ; glycoside TFA derivatives ; enantioselective gas chromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The volatile constituents of lulo del Chocó (Solanum topiro) fruit pulp obtained by liquid-liquid extraction were analyzed by capillary GC and capillary GC-MS. In total, 30 components were identified with methyl salicylate, hexadecanoic acid, hexanal, guaiacol, ethyl butanoate, and ethyl acetate being the major components. Chirospecific MDGC analysis revealed the predominance of (R)-ethyl-3-hydroxybutanoate (ee 40%) and the presence of racemic mixtures both of δ-octalactone and of δ-decalactone. For γ-hexalactone, γ-octalactone, and γ-decalactone enantiomeric distributions of 22.4 : 77.6, 22.9 : 77.1, and 20.0 : 80.0, (R) : (S), respectively, were determined. Glycosidically bound aroma compounds were identified by capillary GC and capillary GC-MS after isolation of the glycosidic fraction obtained by Amberlite XAD-2 adsorption and methanol elution followed by hydrolysis with a commercial pectinase enzyme. In total 13 bound aroma compounds (aglycones) were identified. These aglycones mainly consisted of compounds exhibiting aromatic structures. Additionally, with the aid of capillary GC and capillary GC-MS (EI and NCI) of trifluoroacetylated derivatives we identified eight glucosides: the novel 3,6-epoxy-7-megastigmen-5,9-diol β-D-glucopyranoside and the hexyl, benzyl, linalyl oxide (furanic), 2-phenylethyl, vomifolyl (isomer 1), (6S,9R)-vomifolyl, and scopoletin β-D-glucopyranosides.
    Additional Material: 1 Ill.
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  • 60
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    Electronic Resource
    System Peaks of Cyclodextrins in Capillary Electrophoresis (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 409-412 
    Details
    ISSN: 0935-6304
    Keywords: Cyclodextrin ; capillary electrophoresis ; system peak ; CHES 1 ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using a running buffer containing cyclodextrins (CDs) and 2-[N-cyclohexylamino]-ethanesulfonic acid (CHES), positive system peaks were observed in the analysis of a ganglioside mixture by CE-UV. These system peaks were related to CDs in the running buffer because these peaks were also detected when a plug of solution devoid of CDs but having the same CHES concentration and pH as the running buffer was injected. Neutral CDs were separated owing to the formation of inclusion complexes with the anionic CHES ion. One possible explanation for the positive system peaks is that the anionic CD-CHES inclusion complex is displaced by co-ions with higher UV absorptivity.
    Additional Material: 3 Ill.
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  • 61
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    Electronic Resource
    An Introduction to Monolithic Disks as Stationary Phases for High Performance Biochromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 27-38 
    Details
    ISSN: 0935-6304
    Keywords: Monolith ; continuous bed column ; convective interaction media ; membrane chromatography ; membrane adsorber ; HPMDC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monolithic stationary phases have revolutionized protein chromatography because they combine speed, capacity, and resolution in a unique manner. Since such stationary phases contain no particles but only flow-through pores, the usual mass transfer restrictions to the chromatography of large molecules are not observed and extremely fast separations become possible. Recently the area of application of monolith chromatography has been extended to the separation and analysis of small molecules and plasmid DNA. This review summarizes the state of art in high performance monolith and especially high performance monolithic disk chromatography (HPMDC). The current understanding of the theory of protein HPMDC is summarized, while an introduction to the evolving field of small molecule HPMDC is attempted. The basic differences between the monolithic disks and columns packed with conventional stationary phases (including perfusion and micropellicular particles) but also monolithic columns (porous rods) are outlined. Finally, the potential of HPMDC to analytical and preparative biochromatography is demonstrated by a discussion of recent applications of chromatographic disks for protein isolation and bioprocess analysis.
    Additional Material: 14 Ill.
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  • 62
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    Electronic Resource
    Miniaturized Molecularly Imprinted Continuous Polymer Rods (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 44-46 
    Details
    ISSN: 0935-6304
    Keywords: In situ molecular imprinting ; continuous polymer rod ; miniaturized column ; chiral recognition ; diastereoselectivity ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Molecularly imprinted continuous polymer rods are prepared inside PEEK tubes of 1 mm i. d. by an in situ preparation technique; and chiral separations on such media have been demonstrated. The miniaturized column filled with (-)-cinchonidine-imprinted or (+)-cinchonine-imprinted polymer rods based on a copolymer of 2-(trifluoromethyl)acrylic acid and ethylene glycol dimethacrylate permitted diastereoseparation of (-)-cinchonidine and (+)-cinchonine; the template molecule is retained to a greater extent than the corresponding antipode. Increasing the amount of cyclohexanol in the polymerization mixture decreased the backpressure of the resultant rod and the addition of latex beads suspended in water to the prepolymerization mixture affected the selectivity and affinity of the imprinted polymer rods. The column length is adjusted easily by cutting, thus allowing easy control of retention behavior and analysis time.
    Additional Material: 1 Ill.
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  • 63
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    Electronic Resource
    Enantiomeric Separations of Acidic and Neutral Compounds by Capillary Electrochromatography with β-Cyclodextrin-Bonded Positively Charged Polyacrylamide Gels (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 59-66 
    Details
    ISSN: 0935-6304
    Keywords: Enantiomeric separation ; capillary electrochromatography ; positively charged polyacrylamide gel ; allyl carbamoylated β-cyclodextrin derivatives ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The novel enantiomeric separation of acidic and neutral compounds by capillary electrochromatography with β-cyclodextrin-bonded positively charged polyacrylamide gels was examined. The columns used are capillaries filled with a positively charged polyacrylamide gel, a so-called monolithic stationary phase, to which allyl carbamoylated β-CD derivatives covalently bind. The capillary wall was activated first by bifunctional reagent to make the resulting gel bind covalently inside the fused-silica tubing. Enantiomeric separations of sixteen acidic and two neutral compounds were achieved using the above-mentioned columns and 200 mmol dm-3 Tris-300 mmol dm-3 boric acid buffer (pH 8.1) as a mobile phase. High efficiencies of up to 150 000 plates m-1 were obtained for dansyl-DL-amino acids. The within-run and between-run reproducibilities of retention time and separation factor were examined for three dansyl-DL-amino acids and warfarin. The relative standard deviations of the within-run and between-run reproducibilities of retention time were less than 1.2 and 1.3% over the six injections, respectively. Those of the separation factor were less than 0.3 and 0.2%, respectively. The gel-filled capillaries were stable for at least four months with intermittent use.
    Additional Material: 6 Ill.
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  • 64
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    Electronic Resource
    Comparison of Different Di-tert-butyldimethyl-Silylated Cyclodextrins as Chiral Stationary Phases in Capillary Gas Chromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 569-575 
    Details
    ISSN: 0935-6304
    Keywords: Enantioselective gas chromatography ; cyclodextrins ; heptakis(2,6-di-O-tert-butyldimethylsilyl)-β-cyclodextrin ; heptakis(2,6-di-O-tert-butyldimethylsilyl-3-O-methyl)-β-cyclodextrin ; heptakis(3,6-di-O-tert-butyldimethylsilyl-2-O-methyl)-β-cyclodextrin ; octakis(2,6-di-O-tert-butyldimethylsilyl-3-O-methyl)-γ-cyclodextrin ; thermodynamic parameters ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Separation factors and thermodynamic data for the separation of various chiral analytes on different di-O-tert-butyldimethyl-silylated cyclodextrin derivatives are collected and described. Modifying the substitution pattern of the tert-butyldimethylsilyl group in position 2 and 3 or changing from β- to γ-cyclodextrin significantly affects the separation properties of the cyclodextrin derivatives.
    Additional Material: 9 Ill.
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  • 65
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    Electronic Resource
    Synthesis and Silica-Based Immobilization of Monofunctionalized Heptakis(2,6-di-O-methyl-3-O-pentyl)-β-cyclodextrin for Enantioselective Capillary-HPLC (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 583-589 
    Details
    ISSN: 0935-6304
    Keywords: Monofunctionalized cyclodextrins ; enantioselective capillary-HPLC ; immobilized chiral stationary phases ; separation of chiral drugs ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Heptakis(2,6-di-O-methyl-3-O-pentyl)-β-cyclodextrin was monofunctionalized by the regioselective introduction of exactly one ω-epoxyoctyl group at the primary site of the cyclodextrin. The site-specifically substituted cyclodextrin was immobilized to commercially available aminopropyl silica by nucleophilic opening of the epoxy function of the spacer substituent resulting in a lipophilic chiral stationary phase with broad applicability for enantiomer separations in capillary-HPLC under reversed-phase conditions.
    Additional Material: 6 Ill.
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  • 66
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    Electronic Resource
    Determination of Lucidin in Rubia tinctorum Aglycones by an HPLC Method with Isocratic Elution (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 600-602 
    Details
    ISSN: 0935-6304
    Keywords: HPLC separation ; lucidin ; Rubia tinctorum ; anthraquinones ; isocratic elution ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---An HPLC method has been developed for the separation of anthraquinones with particular attention to the determination of lucidin in commercially available sources of Rubia tinctorum aglycones. Variations of chromatographic conditions have been studied in order to provide suitable resolution of anthraquinones under isocratic conditions on an end-capped RP C18-column.
    Additional Material: 2 Ill.
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  • 67
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    Electronic Resource
    The Determination of Benzoic Acid in Lemon Flavored Beverages by Stir Bar Sorptive Extraction-CGC-MS (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 644-646 
    Details
    ISSN: 0935-6304
    Keywords: Stir Bar Sorptive Extraction (SBSE) ; thermal desorption (TD) ; capillary GC-MS ; benzoic acid ; beverages ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Stir Bar Sorptive Extraction (SBSE), a recently introduced solventless extraction technique, was applied for the enrichment of benzoic acid in lemon flavored beverages. The stir bar is covered with 50 mg polydimethylsiloxane (PDMS) and the extraction mechanism is similar to that of solid phase micro extraction (SPME) but the enrichment factor is ca. 100 times higher. SBSE is followed by thermal desorption (TD)-capillary gas chromatography (CGC)-mass spectroscopy (MS). Calibration graphs for benzoic acid were linear from 1 to 1000 ppm for water and diluted soft drinks and the repeatability (n = 6) was less than 5% RSD.
    Additional Material: 2 Ill.
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  • 68
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    Separation of Ceramides by Sub-Ambient Temperature-Assisted Large Volume Injection in Temperature-Programmed Packed Capillary Liquid Chromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 653-655 
    Details
    ISSN: 0935-6304
    Keywords: Packed capillary LC ; large volume injection ; temperature programming ; ceramides ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 1 Ill.
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  • 69
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    A Simple Way to Speed up Separations by GC-MS Using Short 0.53 mm Columns and Vacuum Outlet Conditions (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 677-680 
    Details
    ISSN: 0935-6304
    Keywords: Capillary ; fast separations ; mass spectrometry ; vacuum ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---There is a constant drive to speed up GC separations. Shorter analysis times provide more analyses per day, which reduces cost. One approach is to reduce column length and column diameter and columns of 0.15 mm i.d. have indeed grown in popularity. However, the majority of applications are still done with 0.25 mm and 0.32 mm columns.
    Additional Material: 10 Ill.
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  • 70
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    Fast Separation of Nucleosides by Capillary Electrochromatography on Non-Endcapped Phenyl-Bonded Silica Phase Using Short-End Injection Method (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 138-142 
    Details
    ISSN: 0935-6304
    Keywords: Capillary electrochromatography ; nucleosides ; short-end injection ; phenyl-bonded silica ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The influence of several experimental parameters (pH, ionic strength, organic modifier content of hydro-organic buffer) upon EOF, migration time, and retention factor has been studied in CEC with a phenyl-bonded silica column on a model mixture of five nucleosides. This paper illustrates the current interest in CEC as a method of resolving complex mixtures of neutral and ionic solutes and demonstrates the potential of the short-end injection method as a means of reducing analysis time.
    Additional Material: 4 Ill.
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  • 71
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    Separation of Anthraquinones by Capillary Electrophoresis and High-Performance Liquid Chromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 143-148 
    Details
    ISSN: 0935-6304
    Keywords: Analysis of anthraquinones ; capillary electrophoresis ; high-performance liquid chromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The separation and determination of twelve anthraquinones, viz. anthraquinone 1, chrysphanol 2, aloe-emodin 3, alizarin 4, anthraquinone-2-carboxylic acid 5, purpurin 6, sennoside B 7, sennoside A 8, emodin 9, quinalizarin 10, rhein 11, and anthraflavic acid 12, were achieved by capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC). Detection at 260 nm with a buffer solution containing 30 mM sodium borate (adjusted to pH = 10.56 with 0.05N NaOH) and acetonitrile (9 : 1) in CE or with a linear gradient elution containing 20 mM KH2PO4 with 0.05% phosphoric acid (pH = 2.91) and methanol in HPLC was found to be the most suitable approach for this separation. Contents of six components (2, 3, 7, 8, 9, 11) in crude Rhei Rhizoma extract could easily be determined within 39 min by CE or 63 min by HPLC. The effects of buffers on this separation and the validation of the two methods were studied.
    Additional Material: 5 Ill.
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  • 72
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    Electronic Resource
    Biodegradation of Pharmaceutical Residues Investigated by SPE-GC/ITD-MS and On-Line Derivatization (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 474-478 
    Details
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Solid-phase extraction, on-line derivatization, and measurement by ion trap mass spectrometry (ITD-MS) were used to investigate the biological degradation of pharmaceutical residues (clofibric acid, ibuprofen, diclofenac). The results of the single steps of sample pretreatment and analytical determination are reported. MS/MS measurements were performed on an ITD-MS by selecting collision induced dissociation of the molecular ions (M+) as parent ions to defined daughter ions. A pilot sewage plant and biofilm reactors operating under oxic and anoxic conditions were run as model systems with synthetic sewage water containing 10 to 50 mg/L dissolved organic carbon (DOC) and pharmaceuticals in concentrations of 10 μg/L. Clofibric acid displayed its persistent character in all cases. The pilot sewage plant and the oxic biofilm reactor showed comparable results for diclofenac and ibuprofen, which both were partly degraded. These results can explain the occurrence of these substances in sewage effluents and in the aquatic environment. A high degree of degradation was found especially for ibuprofen in the oxic biofilm reactor, which was attributed to adaptation of the biofilm to the residue. Two metabolites of ibuprofen could be identified on the basis of their mass spectra and comparison with literature data, viz. hydroxyibuprofen and carboxyibuprofen.
    Additional Material: 8 Ill.
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  • 73
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    Electronic Resource
    Characterization of Polydimethylsiloxanes Using an Off-Line Combination of Supercritical Fluid Chromatography with Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 502-506 
    Details
    ISSN: 0935-6304
    Keywords: Silicone oil ; supercritical fluid chromatography (SFC) ; micropacked columns ; MALDI-TOF ; GC/MS ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 4 Ill.
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  • 74
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    Separation and Detection of Metal Ions in Ecological Samples by Capillary Zone Electrophoresis with Indirect UV Detection (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 511-514 
    Details
    ISSN: 0935-6304
    Keywords: CZE ; indirect UV detection ; metal ions ; ecological samples ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 5 Ill.
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  • 75
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    Electronic Resource
    The Need for Two-Dimensional Gas Chromatography: Extent of Overlap in One-Dimensional Gas Chromatograms (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 235-244 
    Details
    ISSN: 0935-6304
    Keywords: Comprehensive two-dimensional GC ; peak overlap ; statistical-overlap theory ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The need for two-dimensional gas chromatography is justified by the extent of peak overlap in one-dimensional gas chromatograms (GCs) of complex mixtures. Such overlap was predicted long ago by statistical-overlap theory (SOT). In this paper, SOT is conceptually reviewed and its predictions are shown to be quantitatively accurate. GCs of complex mixtures of polychlorinated biphenyls, pyridine- and nitrogen-containing polynuclear aromatic hydrocarbons, tetrachlorodibenzo-p-dioxins and dibenzofurans, fatty acid methyl esters, flavors and fragrances, and naphtha were simulated by commercial GC software on DB-1, DB-5, and Stabilwax stationary phases. The numbers of peak maxima in the GCs agreed with predictions of SOT, when the interval of time between successive peaks of pure compounds was described by Poisson statistics. This agreement was realized even though the time intervals actually are deterministic, not statistical. In addition, the numbers of mixture components were predicted with accuracy by regression of peak numbers against SOT. Similar regressions have been reported before, but the theory used here is more sophisticated and its predictions consequently are more accurate. Future directions for finalizing SOT are suggested.
    Additional Material: 4 Ill.
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  • 76
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    Enantioselective HRGC Separation of Toxaphene Congeners by Ethylated γ-Cyclodextrins (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 304-308 
    Details
    ISSN: 0935-6304
    Keywords: Enantioselectivity ; gas chromatography ; ethylated γ-cyclodextrin ; toxaphene ; enantiomers ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The enantioselectivity of three batches of octakis-(2,3,6-tri-O-ethyl)-γ-cyclodextrin (TEG-CD), which differed significantly in their degree of ethylation, is reported for toxaphene congeners. The cyclodextrin composition was determined by high performance liquid chromatography-mass spectrometry. Columns prepared with almost fully ethylated cyclodextrin showed no enantiomer separation. Increasing the average number of free OH groups up to an optimum of 3.8 allowed to resolve the following toxaphene congeners into enantiomers: Parlar no. 11, 12, 15, 21, 25, 32, 38, 42.1, 42.2, 50, 51, 56, 58, 59, 62, 69 as well as B8-1412. More free OH groups did not improve the enantiomer resolution. The structure of the polysiloxane used for dilution of TEG-CD also had an influence on the enantiomer separations achieved. Compared to OV 1701-OH, the use of PS 086 significantly improved the enantiomer resolutions of the separated congeners. However, neither increasing the column length nor the cyclodextrin amount in the stationary phase led to better separation results.
    Additional Material: 2 Ill.
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  • 77
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    Reversed-Phase High-Performance Liquid Chromatographic Separation and Determination of 4-Amino-azobenzene-4′,5-disulfonic Acid and Related Products in Industrial Wastewater Effluents (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 329-332 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; industrial wastewater ; process development ; 4-amino-azobenzene-4′,5-disulfonic acid (AABDS) ; 4-amino-azobenzene (AAB) ; 4-amino-azobenzene-4′-sulfonic acid (AABS) ; 4-amino-azobenzene-4′,3,5-trisulfonic acid (AABTS) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A simple and rapid reversed-phase high-performance liquid chromatographic method for the separation and determination of 4-amino-azobenzene-4′,5-disulfonic acid (AABDS) and its process-related impurities was developed. The separation was achieved on a μ-Bondapak C18 column using 0.15 M ammonium sulfate-acetonitrile (55:45) (v/v) as eluent. A UV-visible spectrophotometric detector fixed at 386 nm was used both for detection and quantitation. The method was used not only for quality assurance but also for process development and wastewater management of AABDS.
    Additional Material: 4 Ill.
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  • 78
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    Electronic Resource
    Mixed Mode Retention and the Use of Competing Acid for the Ag+-HPLC Analysis of Underivatized Conjugated Linoleic Acids (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 317-323 
    Details
    ISSN: 0935-6304
    Keywords: Conjugated linoleic acids ; underivatized ; Ag+-HPLC ; resolution ; mixed mode retention ; hydrogen bonding ; competing acid ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Fatty acids (FAs) and fatty acid residues are generally methylated and analyzed by GC. The reasons for this are partly historic and partly because of the sensitivity advantage of flame ionization detection over UV absorption by the carboxylic acid functionality in saturated FAs. However, for strongly absorbing unsaturated acids such as the conjugated linoleic acids (CLAs), the sensitivity advantage is greatly reduced. Hence there seems little reason to waste time and introduce errors associated with methylation. Remarkably, this appears not to have been recognized. In this paper we describe our method development for the analysis of underivatized CLAs by silver ion HPLC separation on the ChromSpher Lipids column. Using mobile phases previously optimized for the analysis of the methylated CLAs, retention is excessive and a competing acid is required. Various combinations of small concentrations of acetic acid (3.0-2.5%) with acetonitrile (0.0-0.025%), respectively, yield similar resolution and run times. As well as its role as a competing acid, acetic acid acts as a general strong solvent and thus can be used alone as a modifier (without acetonitrile). However, for slightly shorter run times a mobile phase of 2.5% acetic acid and 0.025% acetonitrile was chosen as the optimum mobile phase for analysis. The separation of the free CLAs is clearly superior to those previously published and obtained in this study for the methylated CLAs. The additional specific strong interactions of the underivatized CLAs seem certain to be due to hydrogen bonding between the CLA carboxylic acid functionality and the large number of residual silanols on the surface of the silica support of the stationary phase.
    Additional Material: 6 Ill.
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  • 79
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    Design, Preparation and Application of a New π-Basic Chiral Stationary Phase for the Liquid Chromatographic Separation of Enantiomers (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 333-337 
    Details
    ISSN: 0935-6304
    Keywords: Liquid chromatography ; chiral separation ; chiral stationary phase ; separation of enantiomers ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A new reciprocal π-basic chiral stationary phase (CSP) was designed based on the reciprocity conception of chiral recognition and prepared starting from (S)-leucine. The CSP thus prepared was applied in resolving various π-acidic N-(3,5-dinitrobenzoyl)-α-amino amides and esters and found to be very effective. Especially, N-(3,5-dinitrobenzoyl)-α-amino N,N-dialkyl amides were resolved very well on the new reciprocal CSP. From the chromatographic resolution results and based on the reciprocity conception of chiral recognition with the aid of Corey/Pauling/Koltan (CPK) molecular model studies, a chiral recognition mechanism which utilizes π-π interaction and simultaneously two hydrogen bonding interactions between the CSP and the analyte has been proposed. The CSP prepared in this study was also successful in resolving 3,5-dinitrophenylcarbamate derivatives of 2-hydroxycarboxylic acid esters.
    Additional Material: 4 Ill.
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  • 80
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    Fiber Conditioners for Solid Phase Microextraction: Design, Testing, and Application (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 343-347 
    Details
    ISSN: 0935-6304
    Keywords: SPME ; desorption ; fiber conditioning ; field sampling ; sample preparation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 81
    Electronic Resource
    Electronic Resource
    Silver Ion High-Performance Liquid Chromatographic Separation of Conjugated Linoleic Acid Isomers, and other Fatty Acids, after Conversion to p-Methoxyphenacyl Derivatives (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 348-352 
    Details
    ISSN: 0935-6304
    Keywords: Silver ion high-performance liquid chromatography (Ag-HPLC) ; conjugated linoleic acid (CLA) ; p-methoxyphenacyl derivatives ; single-column Ag-HPLC ; fatty acid analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 82
    Electronic Resource
    Electronic Resource
    Relationships between Retention Factors and Analyte Hydrophobicity on Cyanopropyl and n-Octadecyl Bonded Silicas, Cross-Linked Polymers and Porous Graphitic Carbon Stationary Phases. Consequences for the Trace Analysis of Highly Polar Organic Compounds (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 437-444 
    Details
    ISSN: 0935-6304
    Keywords: Retention factors ; styrene divinylbenzene polymer ; porous graphitic carbon ; solid-phase extraction ; water analysis ; polar organic compounds ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---LC retention data have been measured using various stationary phases with an emphasis on highly polar to moderately polar neutral organic compounds having octanol-water partition coefficients (Kow) in log units between 0 and 3. The relationships between the retention factor measured in water and the octanol-water partition coefficient are linear but with different slopes for octadecyl (C18) silicas, and two polystyrene divinylbenzene (PS-DVB) phases with low and high surface areas. These relationships confirm that highly cross-linked polymers can provide more than 1000-times higher retention values than C18 silicas for moderately polar analytes but close values for highly polar ones. They also explain why C18 silicas and polymers are equivalent for the separation of very polar analytes. In contrast, due to a different retention mechanism, no relation exists between the retention shown by porous graphitic carbons (PGC) and analyte hydrophobicity, but highly polar analytes are in general much more strongly retained than by any other sorbent. The potential of PGC for both the extraction and the separation of analytes is shown. Due to the difference in separation mechanism, PGC is the analytical phase that should be used for confirmation of the identity of analytes instead of a cyanopropylsilica column as recommended in some environmental procedures. Applications are presented for the trace-determination of triazines and polar degradation products in ground and surface water with detection limits below the 0.1 μg/L level.
    Additional Material: 5 Ill.
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  • 83
    Electronic Resource
    Electronic Resource
    Studies on the Use of Commercial Capillary Gas Chromatographic Columns as Diffusion Denuders (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 449-454 
    Details
    ISSN: 0935-6304
    Keywords: Denuders ; isolation and enrichment ; analysis ; volatile organic compounds ; partition coefficients Kfs ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The possibility of using a piece of gas chromatographic capillary column as a tubular denuder for isolation and enrichment of organic pollutants present in air was studied. The partition coefficients (Kfs) of typical organic pollutants (benzene, chlorobenzene, toluene) between the gaseous phase and the denuder sorption layer were determined and effects of analyte concentration in the gaseous phase and gas flow rate on partitioning were studied. The partition coefficients were found to be constant in the studied range of concentration and gaseous mixture flow rate. A piece of a capillary column coated with polydimethylosiloxane can be used as a tubular denuder.
    Additional Material: 2 Ill.
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  • 84
    Electronic Resource
    Electronic Resource
    Headspace Sorptive Extraction (HSSE) in the Headspace Analysis of Aromatic and Medicinal Plants (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 539-546 
    Details
    ISSN: 0935-6304
    Keywords: Headspace sampling ; Headspace Sorptive Extraction (HSSE) ; SPME ; aromatic plants ; medicinal plants ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A new sampling technique, Headspace Sorptive Extraction (HSSE), is here applied for the first time to the headspace sampling of medicinal and aromatic plants. The analyte partition coefficient between HSSE-PDMS stir bar and sample headspace (K1), the concentration factor (CF), the reproducibility, and the minimum recoverable amount were determined by analyzing standard solution of high volatility C5-C7 compounds with different polarities and structures (cyclohexane, propyl acetate, hexanal, 1-hexen-3-ol, isoamyl acetate, and 2-heptanol). Four aromatic and medicinal plants, viz. rosemary (Rosmarinus officinalis L.), sage (Salvia officinalis L.), thyme (Thymus vulgaris L.), and valerian (Valeriana officinalis L.) were analyzed by HSSE-GC with PDMS stir bars, and their concentration capacity was compared with those of S-HS and HS-SPME with different fibers. HSSE showed very high concentration capability with both standard and real sample components.
    Additional Material: 3 Ill.
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  • 85
    Electronic Resource
    Electronic Resource
    Considerations on Static and Dynamic Sorptive and Adsorptive Sampling to Monitor Volatiles Emitted by Living Plants (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 547-553 
    Details
    ISSN: 0935-6304
    Keywords: Capillary GC ; static and dynamic headspace sampling ; sorptive and adsorptive extraction ; plant volatiles ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Static and dynamic headspace sampling have been applied for the enrichment of volatiles emitted by living plants. For solid phase microextraction (SPME) the sorptive fibers polydimethylsiloxane (PDMS) and polyacrylate (PA) have been compared and, in accordance with the like-like principle, polar compounds exhibit more affinity for the PA fiber while apolar solutes favor the PDMS fiber. For dynamic sampling, tubes packed with PDMS particles show greater inertness than Tenax; some Tenax decomposition products, e.g. benzaldehyde and acetophenone, interfere with the analyses. With PDMS particles operated in the breakthrough mode, the obtained profiles are similar to those obtained by SPME on the PA fiber. Recoveries relative to a packed PDMS bed are 85% for Tenax, 2.4% for SPME-PDMS, and 6.2% for SPME-PA.
    Additional Material: 5 Ill.
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  • 86
    Electronic Resource
    Electronic Resource
    Determination of Cinnamomi Constituents by High-performance Liquid Chromatography and Capillary Electrophoresis (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 561-564 
    Details
    ISSN: 0935-6304
    Keywords: Retention factors ; Cinnamomi ramulus ; high-performance liquid chromatography ; capillary electrophoresis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 3 Ill.
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  • 87
    Electronic Resource
    Electronic Resource
    Ion Chromatography of Inorganic Anions on Graphitic Carbon as the Stationary Phase (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 590-594 
    Details
    ISSN: 0935-6304
    Keywords: Ion chromatography ; graphitic carbon stationary phases ; anions ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Inorganic anions could be separated on porous graphitic carbon stationary phases in ion chromatography. Ion exchange between eluent anions and sample anions on the stationary phase was confirmed by the retention behavior and the possibility of indirect photometric detection. The elution order of anions was different from that observed for commercially available anion exchangers. Chloride, nitrate, and sulfate contained in tap water could be determined in 7 min.
    Additional Material: 6 Ill.
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  • 88
    Electronic Resource
    Electronic Resource
    Identification and Determination of Active Components in Gentiana rigescens Franch by Micellar Electrokinetic Chromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 697-698 
    Details
    ISSN: 0935-6304
    Keywords: Gentiana rigescens Franch ; gentiopicroside ; swertiamarin ; MEKC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 89
    Electronic Resource
    Electronic Resource
    Applications of PTV Injectors for Problem Solving in the Petrochemical Industry. Thermal Desorption with GC and GC-MS (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 479-484 
    Details
    ISSN: 0935-6304
    Keywords: Programmable temperature vaporizing injection (PTV) ; thermal desorption ; gas chromatography ; mass spectrometry ; plasticizers ; polyethylene ; food wrapping film ; explosive powders ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Programmable Temperature Vaporizing Injection (PTV) has been used extensively as a means of injecting large volumes of samples to enhance sensitivity. This paper describes the use of PTV injection in the desorption mode for the analysis of a range of solid samples, and four examples of this application are described in detail. Detection by mass spectrometry was used extensively as a means of identification of the components in the various samples which were characterized.
    Additional Material: 12 Ill.
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  • 90
    Electronic Resource
    Electronic Resource
    A Few Milestones on the Journey of Chromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 497-501 
    Details
    ISSN: 0935-6304
    Keywords: Historical remarks ; modern separation methods ; gas chromatography ; selective sorbents ; selectors ; discovery process ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The research conducted and the discoveries during the development of chromatography are briefly surveyed, with emphasis being placed on gas chromatography. Some actors are presented who played major roles en route from Tswett's original discovery to modern separation methods. The article is based mainly on personal memories and encounters. A few examples of the participation of our country in the development of chromatography are mentioned as well as international contacts. Some remarks are made on the use of selective sorbents or selectors in modern analytical separations. The paper closes with a few comments on the “philosophy” of the discovery process.
    Additional Material: 1 Tab.
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  • 91
    Electronic Resource
    Electronic Resource
    Group-Type Identification of Oil Samples Using Comprehensive Two- Dimensional Gas Chromatography Coupled to a Time-of-Flight Mass Spectrometer (GC×GC-TOF) (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 507-510 
    Details
    ISSN: 0935-6304
    Keywords: Comprehensive two-dimensional GC ; time-of-flight ; oil analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---In this work a comprehensive two-dimensional system (GC×GC) was coupled to a time-of-flight mass spectrometer (TOF/MS) for the analysis of oil samples. Group-types like the alkanes and saturated cyclic compounds (naphthenes), which are present in oil, are shown separately by selecting their unique masses. On selecting appropriate ion fragments, this method also permits the determination of sulfur- and oxygen-containing species in oil. Former results obtained by FID detection could be confirmed. After proper selection of unique ions in GC×GC-TOF both selectivity and sensitivity increase.
    Additional Material: 6 Ill.
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  • 92
    Electronic Resource
    Electronic Resource
    Open Tubular Supercritical Fluid Chromatography (ot-SFC) Applied to the Separation of Coal-Derived Products Obtained by Supercritical Fluid Extraction (SFE) (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 515-518 
    Details
    ISSN: 0935-6304
    Keywords: Capillary supercritical fluid chromatography (c-SFC) ; coal analysis ; SFE ; instrumentation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---This work describes the construction and evaluation of a simple and versatile capillary supercritical fluid chromatographic (SFC) system and its application to the analysis of liquid fuels obtained by SFE. The modular supercritical fluid chromatography (SFC) system uses a syringe pump, a fused silica capillary column (100 μm i.d., coated with a 0.2-μm thick film of 5% phenylpolymethylsiloxane), a FID detector, and a high pressure injection valve with a 60-nL internal loop. Coal-derived samples were obtained by supercritical fluid extraction (SFE) of a Brazilian high-inertinite coal from Amando Simões mine, located in Paraná state (Brazil) using toluene as solvent and operating in the static mode. SFE was followed by preparative liquid chromatography fractionation into eight discrete fractions (PLC-8 method). Two of those fractions (F-2 and F-8) were used to evaluate the proposed set-up. The system described proved to be simple, easy-to-use, and versatile when used in the analysis of a range of samples from low molecular weight-low volatility (F-2) to higher molecular weight-high polarity asphaltols (F-8).
    Additional Material: 3 Ill.
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  • 93
    Electronic Resource
    Electronic Resource
    Linear and Quadratic Relationships between Retention and Organic Modifier Content in Eluent in Reversed Phase High-Performance Liquid Chromatography: A Systematic Comparative Statistical Study (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 667-676 
    Details
    ISSN: 0935-6304
    Keywords: Reversed-phase high performance liquid chromatography (RP-HPLC) ; relationships between retention and eluent composition ; linear and quadratic models ; statistical comparison of ; evaluation of HPLC columns ; stationary phases ; lipophilicity/hydrophobicity ; log kw ; log P ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Statistical evaluation of linear and quadratic models of chromatographic retention was performed. The relationships describing retention were derived for a set of 23 carefully selected test analytes chromatographed on 18 HPLC columns using methanol-water or acetonitrile-water solutions as mobile phase. It was ascertained whether the square term in the quadratic model improves the description of chromatographic retention in a statistically significant manner. It was also checked whether the retention data extrapolated to a hypothetical neat water eluent (log kw) obtained with the two models and the two organic modifiers are equivalent or should be considered different. The research proved that both models yield similar results and the extrapolated log kw values do not differ statistically significantly in the case of methanol-containing mobile phases. In the case of acetonitrile-water systems the log kw values obtained with linear and quadratic models are normally statistically different. Correlation analysis for log kw vs. log P parameters was performed for data determined on six columns. The best correlations were achieved employing log kw data derived with the linear model for methanol/water systems.
    Additional Material: 3 Ill.
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  • 94
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    Electronic Resource
    Determination of Molecular Weight Distribution of Lignin Derivatives by Aqueous Phase High Performance Size Exclusion Chromatography (HPSEC) (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 693-696 
    Details
    ISSN: 0935-6304
    Keywords: High performance size exclusion chromatography ; molecular weight ; lignin derivatives ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 4 Ill.
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  • 95
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    Electronic Resource
    Identification and Quantification of Thiaarenes in the Flue Gas of Lignite-Fired Domestic Heating (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 457-473 
    Details
    ISSN: 0935-6304
    Keywords: Domestic lignite heating emissions ; isokinetic sampling ; polyaromatic sulfur heterocycles (PASH) ; thiaarenes ; atomic emission detection (AED) ; pulsed flame photometric detection (PFPD) ; high resolution mass spectrometry (HRMS) ; retention indices ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Lignite briquettes with different sulfur contents were burned in a common type of domestic heating system. The levels of polycyclic aromatic sulfur heterocycles (PASH, thiaarenes) and their alkylated and phenylated derivatives in the flue gas were determined. The analytical method described comprises isokinetic sampling, GC/full scan-MS for screening analysis, HPLC/wavelength programmable fluorescence detection (selected PAHs used as internal standards for GC), GC/atomic emission detection or GC/pulsed flame photometric detection (sulfur-selective detection of thiaarenes), GC/high resolution MS (verification and quantification of thiaarenes), and the determination of the gas chromatographic retention indices. In total 57 thiaarene species (individual compounds if possible and groups of isomeric compounds such as alkylated/phenylated species) were identified, their retention indices determined, and quantified as flue gas emission concentrations. Not only thiophene-related thiaarenes but also species with two sulfur atoms in the molecule (e. g. thienothiophene derivatives) were found. The thiaarene emission pattern is discussed, as is the correlation between the thiaarene emissions and the sulfur content of the different briquette types burned.
    Additional Material: 11 Ill.
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  • 96
    Electronic Resource
    Electronic Resource
    Solid-Phase Microextraction of Pyrethroid Pesticides from Water at Low and Sub-ppt Levels at Different Temperatures (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 485-488 
    Details
    ISSN: 0935-6304
    Keywords: Pyrethroids ; solid-phase microextraction ; water analysis ; temperature ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Synthetic pyrethroids are increasingly being used for insect control on field crops because of their advantageous environmental properties such as short field life, broad spectrum of insecticide activity, and relatively low mammalian toxicity. In the present work, experimental conditions were optimized for trace analysis of pyrethroids in water by using solid-phase microextraction followed by capillary gas chromatography. Effects of temperature, SPME-fiber diameter, and matrix were studied. SPME used off-line with a gas chromatograph electron-capture detection (GC-ECD) showed a linear response over a wide concentration range. Our results showed a strong temperature effect on pyrethroid extraction yield. The detection limit after 5 min of SPME-fiber exposure to the samples changed from 1 ppb (at 30°C) to 0.1 ppt (at 90°C), which is a 10000 increase in pyrethroid detection. The standard deviations of the analyte peak area ratios were typically in the range of 1-7% at 30°C and of 3 to 15% at 90°C. Best conditions for pyrethroids analysis were achieved using high temperature solution and a 100 μm polydimethylsiloxane fiber. No matrix (river water) influence was observed on detection of the investigated pyrethroids.
    Additional Material: 6 Ill.
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  • 97
    Electronic Resource
    Electronic Resource
    Advances in Flavor Research (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 489-496 
    Details
    ISSN: 0935-6304
    Keywords: Flavor ; odorant ; headspace ; GC ; interaction ; electronic nose ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---In order to understand the flavor of foods a multitude of scientific investigations have been carried out and a number of analytical tools for flavor research developed in the last few decades. Initially, scientific investigations focused mainly on the identification of all compounds that could contribute to the flavor. Olfactory GC techniques permitted the division of identified volatiles into odor-active and non-odor-active. Many techniques were developed to enhance the quality and the information content of the flavor results. Since the early 1990s, analytical investigations have dealt with interactions between food matrices and flavor compounds and the human influence on the retardation of odorants. New analytical methods concentrate on the headspace of the sample by using static or dynamic headspace analysis, or deal with measurements of volatile release in the mouth by a novel nose sampler and oral vapor GC. These useful tools clarify the effects of breathing, chewing, and saliva flow on flavor release. Though the human nose performs well at low concentrations of odorants, it is a medium-term aim to replace the use of the human nose by analytical techniques. Future investigations will probably deal with the interactions of odorants and the human receptors and it is mainly these receptors that will play a key role in aroma research. By analysis of the effects of odorants on the receptors the mechanisms of odor perception will be elucidated. This will enable the development of supporting analytical tools like electronic noses that really do function as noses, or “neural networks”.
    Additional Material: 9 Ill.
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  • 98
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    Electronic Resource
    Microfabricated Monolith Columns for Liquid Chromatography. Sculpting Supports for Liquid Chromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 19-26 
    Details
    ISSN: 0935-6304
    Keywords: Microfabrication ; monolith ; electrochromatography ; peptides ; reactive ion etching ; reversed phase ; nanocolumns ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monolith columns are generally fabricated by polymerization of monomers within a column. This paper reviews an alternative strategy in which the bed is microfabricated in an inorganic material by ablation. Channels of 1.5 μm width and 10 μm depth were sculpted in quartz by deep reaction ion etching. Using this approach chromatographic beds were constructed in which cubic support structures were created and arranged in rows to mimic particles in a conventional column. Beds ranging from hundreds of thousands to millions of “particles” with volumes of 15 nL to 15 μL were produced. Columns that had been derivatized with an octadecyl silane stationary phase were used to separate both low molecular weight analytes and peptides in the CEC mode. Plate height in the CEC mode was 1.2 μm at maximum efficiency.
    Additional Material: 9 Ill.
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  • 99
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    Electronic Resource
    Dynamic Capacity Studies of CIM (Convective Interaction Media)® Monolithic Columns (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 39-43 
    Details
    ISSN: 0935-6304
    Keywords: Monoliths ; CIM® monolithic column ; dynamic binding capacity ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The characterization of CIM® DEAE monolithic columns in terms of dynamic binding capacity is presented in this paper. Breakthrough experiments were performed for capacity determination. Bovine serum albumin (BSA) was used as a model protein. It is shown that CIM® monolithic columns have good batch-to-batch reproducibility as well as long-term stability. The experiments performed under different linear velocities demonstrated that the dynamic capacity is unaffected at least up to a linear velocity of 2450 cm/h. Furthermore, the breakthrough curve slope is constant, indicating that the capacity would remain constant at even higher linear velocities. The adsorption isotherm of BSA dissolved in 20 mM Tris-HCl buffer shows a constant capacity of around 30 mg/mL of support down to a concentration of 20 μg/mL. The capacity is substantially influenced by the ionic strength; however, 20% of the maximal capacity is still preserved at 0.3 M NaCl.
    Additional Material: 5 Ill.
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  • 100
    Electronic Resource
    Electronic Resource
    Affinity Chromatography of Human Blood Coagulation Factor VIII on Monoliths with Peptides from a Combinatorial Library (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 47-58 
    Details
    ISSN: 0935-6304
    Keywords: Monolith ; factor VIII ; affinity chromatography ; combinatorial peptide library ; peptide synthesis ; recombinant proteins ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: FVIII is a very complex molecule of great therapeutic significance. It is purified by a sequence of chromatographic steps including immunoaffinity chromatography. A peptide affinity chromatography method has been developed using peptides derived from a combinatorial library. Spot technology using cellulose sheets has been applied for this purpose. The dual positional scanning strategy was used for identification of the amino acids in random positions. Approximately 5000 possible candidates found in the first screening round were reduced to a panel of 36. Six candidates have been selected empirically. Five peptides seem to be directed against the light chain of FVIII, one peptide seems to be directed against the heavy chain. The peptides have been immobilized on conventional beaded material and CIM polymethacrylate monoliths. Much better performance with respect to capacity and selectivity has been observed with the monolithic material. Exposure of the ligand and its ensuing accessibility are responsible for these properties.
    Additional Material: 8 Ill.
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