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  • 1990-1994  (47)
  • 1980-1984  (634)
  • 1991  (47)
  • 1980  (634)
  • Physics  (558)
  • Gas chromatography
  • Nuclear reactions
  • 1
    ISSN: 1438-2199
    Keywords: Amino acids ; Cysteic acid analysis ; Taurine analysis ; Gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have reported preparations and gas chromatographic analyses of volatile derivatives of sulfuric acid and taurine (Masuoka et al., 1988; 1989). By extending these studies, we have developed a method for the gas chromatographic determination of cysteic acid. Cysteic acid was converted to the N-isobutoxycarbonyl derivative by the reaction with isobutyl chloroformate in the presence of sodium hydroxide. After desalting with a cation-exchange column, the derivative was converted to the silver salt by reacting with silver oxide. The resulting silver salt was quantitatively esterified with methyl iodide in the presence of dimethyl sulfate and silver oxide. Dimethyl N-isobutoxy-carbonylcysteate [methyl 2-(N-isobutoxycarbonylamino)-3-(methoxysulfonyl) propanoate] formed was analyzed by gas chromatography. The calibration curve was linear up to 5.0µmol per ml of cysteic acid and the recovery was more than 95%.
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  • 2
    ISSN: 1438-2199
    Keywords: Amino acids ; Nonprotein amino acids ; α-Aminoisobutyric acid ; Isovaline ; Screening procedure ; Gas chromatography ; Polypeptide antibiotics (peptaibiotics) ; Filamentous fungi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Filamentous fungi of the genusHypocrea were grown on malt extract/peptone agar, the mycelia were extracted with dichloromethane/methanol, and the extracts were totally hydrolyzed with 6 N HCl (110°C, 24 h). The amino acids (AA) released from peptides were converted into theirN(O)-pen-tafluoropropionyl 1-propyl esters and investigated by gas chromatography and gas chromatography/mass spectrometry for the presence of the nonprotein AAα-aminoisobutyric acid (Aib) and its homologue isovaline (Iva). In particular Aib served as specific marker compound for a particular group of fungal peptides named peptaibiotics,i.e. peptides containing Aib and having antibiotic activities. Screening of 24 species ofHypocrea revealed that the majority was capable of producing peptaibiotics. The reliability of the screening procedure was shown with the isolation of peptaibiotics fromHypocrea muroiana andHypocrea nigricans. These findings extend the list of genera of fungi already known to produce Aib-containing peptides and also establish that Aib and Iva are fairly common in the biosphere.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    International archives of occupational and environmental health 63 (1991), S. 27-31 
    ISSN: 1432-1246
    Keywords: Hemoglobin adducts ; Exposure control ; Gas chromatography ; Epoxides ; Alkenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A method for monitoring exposure to ethylene oxide (EO) and propylene oxide (PO) and their corresponding alkenes through the analysis of adducts to N-terminal valine in hemoglobin (Hb) using gas chromatography (GC) and electron-capture detection has been developed. The method is a further development of the so-called N-alkyl Edman method, which has thus far been carried out using gas chromatography-mass spectrometry (GC/MS). The correlation between GC and GC/MS determinations of adduct levels in human samples was found to be good. The newly developed GC method enables the determination of adducts to Hb from EO and PO down to levels of about 100 pmol/g globin. This adduct level corresponds to the expected increment from ethene in inhaled tobacco smoke in a smoker of about 10 cigarettes/day or from an average exposure to about 50 Wpb EO or 1 Wpm PO during working hours.
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  • 4
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    Springer
    International archives of occupational and environmental health 62 (1991), S. 603-606 
    ISSN: 1432-1246
    Keywords: Styrene ; Urinary metabolites ; Gas chromatography ; Occupational health
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In support of an occupational investigation of styrene exposure, a capillary gas chromatographic method was developed for the quantitation of the styrene metabolites mandelic and phenylglyoxylic acids. The method was based on that of Guillemin and Bauer [7], in which phenylglyoxylic acid was converted to mandelic acid by reduction before instrumental analysis. The earlier method had to be modified for use with capillary columns; the resulting method was sensitive, selective and reproducible. The detection limit was approximately 0.001 mg/ml urine. Approximately 〈5% relative precision was achieved in the range of 0.05–2 mg/ml urine. Mandelic acid was resolved from other components of urine and from by-products of derivatization.
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  • 5
    Electronic Resource
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    Springer
    International archives of occupational and environmental health 63 (1991), S. 83-88 
    ISSN: 1432-1246
    Keywords: Toluene diisocyanate, TDI ; Toluenediamine, TDA ; Test chamber ; Gas chromatography ; Mass spectromety ; Biological monitoring
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Five men were exposed to toluene diisocyanate (TDI) atmospheres for 7.5 h. The TDI atmospheres were generated by a gas-phase permeation method, and the exposures were performed in an 8-m3 stainless-steel test chamber. The mean air concentration of TDI was ca. 40 μg/m3, which corresponds to the threshold limit value (TLV) of Sweden. The inhaled doses of 2,4- and 2,6-TDI were ca. 120 μg. TDI in the test chamber air was determined by an HPLC method using the 9-(N-methyl-aminomethyl)-anthracene reagent and by a continuous-monitoring filter-tape instrument. After hydrolysis of plasma and urine, the related amines, 2,4- and 2,6-toluenediamine 2,4-, and 2,6-TDA), were determined as pentafluoropropionic anhydride (PFPA) derivatives by capillary gas-chromatography using selected ion monitoring (SIM) in the electron-impact mode. The urinary elimination of the TDAs showed a possible biphasic pattern, with rapid first phases for 2,4-TDA (mean t 1/2 for the concentration in urine, 1.9 h) and for 2,6-TDA (mean t 1/2 for the concentration in urine, 1.6 h). The cumulative amount of 2,4-TDA excreted in urine within 28 h ranged from 8% to 14% of the estimated dose of 2,4-TDI, and the cumulative amount of 2,6-TDA in urine ranged from 14% to 18% of the 2,6-TDI dose. The average urinary level of 2,4-TDA was 5 μg/l in the 6 to 8-h sample (range 2.8–9.6 μg/l), and the corresponding value for 2,6-TDA was 8.6 μg/l (range, 5.6–16.6 μg/l). Biological monitoring of exposure to 2,4- and 2,6-TDI by analysis of 2,4- and 2,6-TDA in urine is feasible.
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  • 6
    Electronic Resource
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    Springer
    The astronomy and astrophysics review 3 (1991), S. 1-46 
    ISSN: 1432-0754
    Keywords: Nucleosynthesis ; Nuclear reactions ; Stars: abundances ; Interstellar Medium: abundances ; Cosmology ; Galaxies: evolution of
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The basic scheme of nucleosynthesis (building of heavy elements from light ones) has held up very well since it was first proposed more than 30 years ago by E.M. Burbidge, G.R. Burbidge, A.G.W. Cameron, W.A. Fowler, and F. Hoyle. Significant advances in the intervening years include (a) observations of elemental and a few isotopic ratios in many more extrasolar-system sites, including metal-poor dwarf irregular galaxies, where very little has happened, and supernovae and their remnants, where a great deal has happened, (b) recognition of the early universe as good for making all the elements up to helium, (c) resolution of heavy element burning in stars into separate carbon, neon, oxygen, and silicon burning, with fine tuning of the resulting abundances by explosive nucleosynthesis in outgoing supernova shock waves, (d) clarification of the role of Type I supernovae, (e) concordance between elements produced in short-lived and long-lived stars with those that increased quickly and slowly over the history of the galaxy, and (f) calibration of calculations of the evolution and explosion of massive stars against the detailed observations of SN 1987A. The discussion presupposes a reader (a) with some prior knowledge of astronomy at the level of recognizing what is meant by an A star and an AGB star and (b) with at least a mild interest in how we got to where we currently are.
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  • 7
    Electronic Resource
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    Archives of toxicology 65 (1991), S. 433-435 
    ISSN: 1432-0738
    Keywords: Analysis ; Blood ; Butoxyacetic acid ; 2-Butoxyethanol ; Gas chromatography ; Glycol ethers ; Man ; Renal clearance ; Toxicokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Venous blood samples from five male volunteers exposed to 20 ppm 2-butoxyethanol (BE) for 2 h were collected at 0, 2, 4, and 6 h from the start of exposure and analyzed by gas chromatography after simultaneous ion-pair extraction and derivatization with pentafluorobenzyl bromide. Butoxyacetic acid (BAA), a major metabolite of BE, was found in all samples except those collected prior to exposure. This is the first time to our knowledge that the analysis of BAA in human blood has been reported. Concentrations of BAA in blood ranged from 22 to 60 μM. These concentrations were about two orders of magnitude lower than those causing swelling and hemolysis of human erythrocytes in vitro. The BAA blood level peaked after 2–4 h. The decrease between 4 and 6 h indicates an average half-time of BAA in blood of about 4 h, which is in accordance with previously observed half-times in urine. The low renal clearance of BAA (22–39 ml/min) indicates extensive binding to blood proteins and poor tubular secretion of the substance. Binding of BAA to blood components is also indicated by the low apparent volume of distribution of approximately 151.
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  • 8
    ISSN: 1573-5133
    Keywords: Polychlorinated biphenyl ; DDT ; Gas chromatography ; Mass spectrometry ; Crossopterygii
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Gas chromatography coupled with electrolytic conductivity detection and electron capture negative chemical ionization mass spectrometry have been used to identify and quantify organochlorine xenobiotics in tissues from two specimens of the living coelacanth Latimeria chalumnae. Compounds identified include polychlorinated biphenyls (PCB), 4,4′-DDT and its metabolites 4,4′-DDD and 4,4′-DDE. Levels of these compounds in the specimens were observed to be generally related to tissue lipid content. Highest concentrations of the xenobiotics were present in the lipid-rich swim bladder, followed by adipose tissue and liver. Levels ranged from 89 to 510 μg kg−1 for PCB and 210 to 840 μg kg−1 for Σ-DDT (including DDD and DDE) on a wet-weight basis. Organochlorine concentrations in relatively lipid-poor tissues, i.e. muscle and kidney, were lower. Parent DDT contributed significantly to the Σ-DDT burden. PCB congeners containing five to seven chlorines were most prevalent. Component distributions did not match those present in common commercial PCB formulations. However, major congeners observed were similar to those reported for other fishes.
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  • 9
    Electronic Resource
    Electronic Resource
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    Chromatographia 31 (1991), S. 171-172 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Ethanolamines ; Ethylene glycols ; Wide-bore capillary column
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The GC separation of a mixture of three ethanolamines and four ethylene glycols without any preliminary derivatization, on a wide-bore capillary column coated with Carbowax 20M is described. These high-boiling and polar compounds elute giving simmetrical peaks and show good resolution. The analysis is completed in less than 14 minutes.
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  • 10
    Electronic Resource
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    Chromatographia 31 (1991), S. 173-176 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Stationary phase optimization ; Mobile phase optimization ; Column temperature optimization ; Multifactor optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A computer-assisted method is presented for the simultaneous multifactor optimization (stationary phase loading, column temperature and carrier gas flow rate) of the analytical conditions for the optimum separation of multicomponent samples in gas chromatography. The optimization of the separation over the experimental region is based on a special polynomial from twelve preliminary experiments using the resolution as the selection criterion. Computer scanning technique was used for optimum selection in three dimensions. Excellent agreement was obtained between the predicted data and the experimental results.
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  • 11
    Electronic Resource
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    Springer
    Chromatographia 31 (1991), S. 193-205 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Column liquid chromatography ; Silanol adsorption centres ; Strongly interacting adsorption sites ; Suppression of adsorption activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary In this second part of the review heterogeneity of the silica surface is described and evidence is presented for the existence of a low population of strong adsorption sites. Methods of detection and determination of these strongly interacting sites are discussed. The last part of the review is devoted to the suppression of unwanted adsorption activity. Methods of blockage and special methods for the preparation of HPLC packings are described.
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  • 12
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    Springer
    Chromatographia 31 (1991), S. 243-246 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Principal component analysis ; Wool wax alcohols ; Sterols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Capillary gas chromatography with flame ionization detection has been applied to the separation of the components of wool wax alcohols. Twenty-six commercial and non-commercial (laboratory) samples were investigated. Twenty-eight components found in the samples were used as variables for further characterization by a chemometric procedure. Principal component analysis was applied to the differentiation of samples from different sources and obtained by different technologies.
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  • 13
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Chemiluminescence detection ; Phosphine derivatives ; Headspace analysis ; Fluorine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Phosphine, alkylated phosphines and monophosphinate esters are detected with high sensitivity in capillary gas chromatography (GC) by their chemiluminescent reactions with molecular fluorine. Detection limits are estimated to be 1.3 pg, 0.5 pg, 8 pg, and 17 pg for phosphine, trimethyl phosphine, trimethyl phosphinate ester, and triethyl phosphine, respectively. As found earlier with alkylated sulfur, selenium and tellurium compounds, the detector exhibits a linear response. For triethyl phosphine, a linear range of greater than three orders of magnitude was demonstrated. Emission spectra were obtained for the trimethyl phosphine and triethyl phosphine systems. Chemiluminescence emitters include electronically excited HCF, vibrationally excited HF, and an unknown species in the trimethyl phosphine system. Banded emission from vibrationally excited HF and a broad continuum were observed for both trimethyl phosphine and triethyl phosphine; however, HCF emission was observed only for TMP. Under the conditions employed, the principal emitter is HCF for trimethyl phosphine and HF and the unknown emitter for triethyl phosphine. This detector may have important applications in investigations of the biogeochemical cycling of phosphorus.
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  • 14
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    Chromatographia 31 (1991), S. 393-397 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Correlation chromatography ; Spark modulator injector
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A spark modulator has been tested as an injection system for correlation gas chromatography. An air/hydrocarbon vapour mixture was used as the carrier gas. Single negative sample injections were performed using a single spark period. The experiments resulted in negative sample peaks and a positive product peak. The intensity of all peaks showed a characteristic dependence on the spark frequency and power used. Ghostpeaks were absent when a correlation experiment was performed with a high concentration of a test compound in pure air. The signal to noise ratio enhancement however, was lower than the theoretical value. More experiments are necessary to expalain this phenomenon.
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  • 15
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    Chromatographia 31 (1991), S. 457-464 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Organoclay stationary phase ; Bentone ; Ethylbenzene and xylene isomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Several kinds of Bentones which have structures similar to Bentone 34 have been tested and compared for the purpose of improving the resolution of ethylbenzene and xylene isomers by gas chromatography. Bentone SD-3 was found to have higher selectivity toward these close-boiling compounds than the well known stationary phase Bentone 34. Modification effects of some conventional stationary phases which represent the whole range of polarity on the chromatographic property of Bentone SD-3 have been investigated and discussed. A number of new organoclays which have different structures of the organic cation in complexes have been synthesized and their properties evaluated for the separation of positional isomers. A simultaneously high selective organoclay for each component in the aromatic mixture of ethylbenzene and xylene isomers, without assistance of conventional stationary phases, has been described.
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  • 16
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    Chromatographia 31 (1991), S. 453-456 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Organochlorine pesticides ; Polychlorinated biphenyls ; Solid phase extraction ; Mussels
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A multi-residue method for the determination of organochlorine pesticides and polychlorinated biphenyls (PCB's) in mussels (Mytilus sp.) is presented. After extraction with acetonitrile, pesticides and PCB's are separated from coextractives by liquid-liquid partition between acetonitrile and water/hexane. Further clean-up is performed using Sep-Pak Florisil cartridges eluting PCB's in the first eluate with hexane and organochlorine pesticides in the second eluate with 15% ethyl ether in hexane. Final determination is carried out by capillary gas chromatography with ECD. Detection limits for different pesticides and PCB's range from 0.02 to 0.3 μg kg−1 and recoveries from standards solutions treated in the same way as the samples averaged 91.5%.
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  • 17
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    Chromatographia 31 (1991), S. 500-504 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Amino acids ; Linearity ; Nitrogen-phosphorus detector
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A significant curvature of the detector response was observed when a Nitrogen-Phosphorus Detector (NPD) was used for the gas chromatographic determination of amino acids. Five calibration standards, over a 16 fold concentration range, were used to calibrate the NPD. A calibration curve of form y=axb was found to be suitable, with coerelation coefficients (r)〉0,997 for all 17 amino acids. A t-test was used to prove that b≠1, i.e. there was significant curvature. This calibration curve reduced calibration errors to less than 6%, compared to more than 40% for linear calibration.
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  • 18
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    Chromatographia 32 (1991), S. 5-12 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Headspace sampling ; GC theory ; Influence of sample volume
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The role of the volume of the sample and the sample vial in equilibrium headspace-gas chromatography is discussed. A new term, thesample phase fraction (ΦS) is introduced. It is shown that if the value of ΦS is kept constant, the vial's volume has no influence on the “sensitivity” of the headspace analysis (which is proportional to the concentration of the analyte in the headspace). In a given headspace sampling system, concentration of the compound of interest in the headspace (c G * ) at equilibrium is related to the value of ΦS: a higher ΦS will increase c G * . However, the influence is important only in the case of low distribution coefficients: in the case of higher distribution coefficients this influence is negligible. This conclusion is also true for small changes in the sample volume in duplicate analyses: exact reproducibility of the sample volume is important only in the case of low distribution coefficient values.
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  • 19
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Supercritical fluid extraction ; GC detectors ; Purity of gases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The usefulness of several grades of carbon dioxide for online supercritical fluid extraction/capillary gas chromatography has been studied. If trace-level work has to be performed, no single grade can be recommended for all modes of detection studied. Good-quality carbon dioxide is available for use with flame ionization and thermionic detectors. With electron-capture detection, however, distinct problems still exist.
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  • 20
    Electronic Resource
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    Springer
    Chromatographia 32 (1991), S. 579-582 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Flame gas analysis ; Low pressure sampling ; Gas syringes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new sampling technique is developed for flame samples taken at very low pressure (50 Torr absolute). This technique uses gas syringes. Analysis is by gas chromatography and the compounds of interest are the fixed gases and selected C1 and C2 hydrocarbons and chlorinated hydrocarbons. Linear response factors are obtained for all compounds. This is highly unusual for gas-phase chlorinated hydrocarbon sampling, which is very prone to sample absorption. The sources of experimental error unique to gas syringe use are identified and quantified. One error source is exacerbated by the very low sample pressure and requires special treatment.
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  • 21
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Linear temperature programming ; Calculation of retention indices
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Program temperature retention indices for fifteen nonalkane solutes have been determined by cubic splines, by other procedures found in the literature and by interpolation of the n-alkanes retention time logarithm for eleven temperature programs. A comparison in terms of variance of the differences between PTRI calculated by CS and each of the remaining methods is made for each of the eleven program runs, for each of the three stationary phases used and for many of the programs. The smallest variances obtained result when the Zenkevich, van den Dool & Kratz and Chen et al. methods are tested. The stationary phase polarity is of no relevance since it has no effect on the specific PTRI found by the different methods employed in this work.
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  • 22
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    Chromatographia 32 (1991), S. 211-214 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Retention index of homologous series ; Chain rigidity ; Stationary phase polarity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The rule that addition of a CH2 group to a molecule increases the retention index by 100±3 is subject to a greater uncertainty than ±3 when (a) the stationary phase has very strong intermolecular attractions comparable to the nitriles and the analyte has a polar group in the 1-position, (b) the alkyl chain to which the CH2 is added has 3 or fewer carbons and (c) when a group that is remote from the end of the chain, such as an ester group or a double bond, introduces rigidity in that part of the chain. In cases (a) and (c), it is still true that the retention index increases linearly in a specific homologous series, but it may deviate from 100 units per carbon by as much as 10 or, in the case of nitrile stationary phases, may be as low as 70.
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  • 23
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    Chromatographia 32 (1991), S. 441-444 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; FID ; Volcanic gas emissions ; Light hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Volcanic gas emissions are strictly related to a specific stage of volcanic activity. Complete knowledge of their chemical composition can be extremely useful for efficient geochemical surveillance of active volcanism sites. A new, effective and simple method for the evaluation of light hydrocarbons in volcanic gases is described. A rapid sampling procedure and GC-FID analysis are employed. Data from different volcanic areas are shown and a their possible correlation is also discussed.
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  • 24
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    Chromatographia 32 (1991), S. 457-460 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Cresol isomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The analysis of isomeric cresols is difficult because of their similar volatilities and high polarities. The situation is specially complicated in the case of industrial synthesisplant samples because of the presence of phenol and of the very high concentration (about 90%) of p-cresol. A gas chromatographic method is described, employing columns packed with Bentone-34 plus Castorwax on diatomaceous supports; the best results are obtained using Chromosorb P AW DMCS. The symmetry of the peaks obtained is excellent for the type of solute.
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  • 25
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Kováts' coefficients ; Stationary phase polarity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A correlation between the retention polarity and the Kováts' coefficient has been found for a number of commercial stationary phases used in gas chromatography. The correlation has been used to predict the polarity of a few mixed stationary phase columns prepared as binary mixtures of OV-101 with OV-25, DC-550 or Carbowax 20M, and also mixtures of OV-225 with SP-2340. A linear relationship was found between polarity and mixture composition. The temperature dependence of the Kováts' coefficient was investigated and found to increase linearly with temperature, the rate of increase depending on the polarity of the stationary phase, with greater increases for more polar stationary phases.
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  • 26
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gas chromatography ; Polycyclic aromatic hydrocarbons ; Soot and air samples ; Liquid CO2 extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The results of the analysis of polycyclic aromatic hydrocarbons (PAH) in soot and similar types of sample are often dependent on the extraction method applied, owing to carbonaceous substances present in these samples. The recoveries of three extraction methods, and ultrasonic ether, a Soxhlet toluene and a Soxhlet extraction with liquid CO2 were compared for a typical soot sample. Additionally the CO2 extraction was optimized with respect to the necessary number of transfers during the extraction and the proper method to remove the CO2 after extraction. Finally, the liquid chromatographic pretreatment of the extract, prior to gas chromatographic analyses of the PAH, was improved.
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  • 27
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    Chromatographia 31 (1991), S. 31-40 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Resolution of enantiomers ; Thermodynamic analysis ; Enthalpy of interaction ; Extrapolation of net retention time
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The calculation of capacity factors, k′, from net retention times, t′R, and the corresponding dead times, tM, at different temperatures suffers from the limited accuracy of the tM values. If the temperature coefficient racy of the tM values. If the temperature coefficient d ln k′/d (1/T) only is required, it is sufficient to determine net retention times (t′R)p at constant inlet pressure pi for different temperatures, since the temperature dependence of (tM)p can be assumed as (tM)p=A·eB/T, with B being approximately independent of the column inlet pressure and of the nature of the carrier gas. The extrapolation and interpolation of (t′R)p may be either performed by linear regression or graphically with a nomogram for ln (t′R)p versus 1/T. The resolution factor, α, of two components, e.g. enantiomers which are resolved on a chiral stationary phase, can be treated in a similar way. Examples are given for the resolution of enantiomers of two non-proteinogenic amino acids on the new polysiloxane phase L-Chirasil-CPG.
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  • 28
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Reversed-phase HPLC ; Antioxidant-tail reducer ; 4-Hydroxy-3,5-di-tert-butylbenzyl alcohol ; Adsorption on diatomaceous supports
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary As an extension of previous work on the deactivation of diatomaceous supports by hydroxy compounds, 4-hydroxy-3,5-di-tert-butylbenzyl alcohol (HBBA) has been evaluated as a potential combined antioxidant tail-reducer. In contrast to diglycerol and the lower molecular weight polyoxyethylene glycols, HBBA is found to be an inefficient tail-reducer. The adsorption of HBBA from solution onto the surface of Phasesep P has been studied and possible explanations for the apparent lack of surface deactivation are offered. A reversed-phase high-performance liquid chromatographic assay for HBBA has been developed and used to monitor the adsorption of HBBA.
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  • 29
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    Chromatographia 32 (1991), S. 248-258 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Electron capture detector ; Hypercoulometry ; Secondary polarisation effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary This paper reports measurements of the current characteristics and of the signal corresponding to a constant concentration of Freon F-11 for an electron-capture detector, supplied with a pulse voltage with a changeable pulse duration, amplitude and repetition time. It was found that an additional voltage applied to the detector cathode increased the detector signal by about 50% and that the maximal signal was observed at 5 V. The influence of the polarized voltage on the electron caputure efficiency coefficient (p) measured with two detectors in series was demonstrated and the reliability of the sample mass calculation by means of (p) is discussed.
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  • 30
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Thin-layer chromatography ; Thermal analysis ; Copper(II) complexes ; Schiff's bases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A study is presented of the thermoanalytical and gas chromatographic (GC) properties of the copper(II) complexes of twenty four tetradenate Schiff's bases. Variations in thermal stability, volatility and GC retention of the complexes are discussed in terms of stereo-electronic effects of the substituents. Although some complexes decomposed extensively during vaporization above 250°C all, apparently, survive chromatography intact at 200°C. Certain complexes were separated as distinct regio-isomers by GC. Fluorinated ligands still appear to be the most suitable derivatizing reagents for Cu(II).
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  • 31
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    Chromatographia 31 (1991), S. 95-97 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Deans sampling and backflushing ; Univap ; Natural gas odorants ; FPD
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The functions of gas sample injection and column backflushing have been combined in a chromatographic system incorporating switching valves only of the three port solenoid type, installed away from injected sample contact. The system pressures are dynamically adjusted during analytic cycles by a simple dome-loaded regulator network. A sulfur analysis (natural gas odorant) application is demonstrated which also includes a foreflush-to-vent sidestream. The coefficient of variation found for the target analytes was less than 0.8%.
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  • 32
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    Chromatographia 31 (1991), S. 123-128 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Amino acids ; Chiral separations ; Fruit juice adulteration ; Microorganisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The configurations of free amino acids (AAs) in orange juice beverages (commercial products of satisfactory and unsatisfactory quality), an orange juice concentrate (bulk product suspected of being adulterated), and in an orange juice that has been contaminated by addition ofLactobacillus plantarum as a model for microbial spoilage, were determined, after derivatization, by means of gas-liquid chromatography (GC) using fused-silica capillary columns coated with Chirasil-L-Val or Chirasil-D-Val as stationary phases. AAs were isolated from juices by treatment with Dowex WX8 ion-exchanger and were investigated, by GC, as theirN(O)-pentafluoropropionylorN(O)-trifluoroacetyl 1-propyl esters. It was found that the high quality orange juice beverage contained L-AAs exclusively whereas this juice, after fermentation withLactobacillus, contained free D-Ala (32.7%), D-Val (62.3%), D-Phe (20.0%), D-Glu (24.3%), D-Ser (2.6%), D-Asp (0.8%), and significant amounts of D-Pro [% D=100 D/(D+L)]. D-Ala (8.8%) and D-Ser (4.2%) were found in a sensory and analytically unsatisfactory orange juice beverage, whilst D-Ala (27.5%) and D-Ser (14.3%) were detected in the orange juice concentrate suspected of being adulterated. Although capillary GC on chiral stationary phases is regarded as being highly suitable for the determination of AA enantiomers in fruit juice beverages, detection of D-AAs is currently not considered as conclusive proof of fruit juice adulteration caused by addition of AA racemates since a non-microbial origin of D-AAs in the respective juice, or an original occurrence of D-AAs, in either the free, substituted, or peptide-bonded form in the fruits, cannot be excluded with certainty.
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  • 33
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    Chromatographia 31 (1991), S. 258-262 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Packed columns ; Methyl polysiloxanes immobilization ; Peroxide initiated cross-linking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The free radical cross-linking procedure of stationary phase immobilization introduced by Grob et al. for capillary columns has been adapted for the preparation of column packings on diatomaceous supports. Immobilization of SE-30 and OV-1 on typical gas chromatography supports: Polsorb B-AW, Chromosorb W-AW, Chromosorb G-AW and Gas Chrom Q was investigated. Before immobilization, the supports (excluding Gas Chrom Q) were purified by extraction with 6 M HCl in a Soxhlet extractor and silanized with hexamethyldisilazane vapour at 300°C. The influence of the type and concentration of peroxide on the efficiency of immobilization of the silicone was studied. In order to obtain over 95% immobilization a minimum of 2% w/w of the peroxide in the stationary liquid is required. Properties of packings with immobilized phase were compared with those of related conventional packings. Adsorption activity, column efficiency and thermal stability were used for this comparison.
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  • 34
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Retention indices ; Target factor analysis ; Reproduction, prediction, classification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Using the method of target factor analysis (TFA) described by Malinowski and Howery a computer program has been developed to study different sets of gas chromatographic retention data. Physico-chemical, topological and uniqueness parameters have been found to be basic factors to describe solute behaviour problems. Factor analytical solutions have been used to reproduce the data matrices and to make predictions based on best sets of basic factors. The mean absolute error in the reproduction step is between 1.72 retention index units (i.u.) for a relatively simple matrix consisting of retention indices of alcohols and 7.36 i.u. for a combined data matrix of alcohol, aldehyde and ketone retention indices. TFA has also been used to classify solutes based on their retention behaviour. Alkanes have been classified from cycloalkanes, alkanes from alkenes, and alcohols from aldehydes and ketones using only their retention data and a special kind of uniqueness vector.
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  • 35
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Non-equilibrium headspace sampling ; Vegetables and food products ; Flavour compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Static headspace sampling combined with gas chromatography using open-tubular (capillary) columns for the characterization of the flavour of raw vegetables and some vegetable products is described. In order to avoid alteration of the composition of the volatiles, the sample was thermostated for a short time only. Although equilibrium between vapour and sample was not established the reproducibility of such conditions is demonstrated. Typical chromatograms are given; the most characteristic compounds present were identified by mass spectrometry.
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  • 36
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    Journal of High Resolution Chromatography 14 (1991), S. 18-24 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Dual-column analysis ; Pesticide analysis ; Organochlorine pesticides ; Temperature optimization ; Flow optimization ; Resolution mapping ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An approach is described for optimizing chromatographic conditions for dual-column analysis of U.S. EPA Method 608 pesticides. Sample throughput for environmental analysis of pesticides can be increased by performing the screening and confirmation analyses at the same time. This requires simultaneous injection, separation, and detection in a GC with dual inlets, columns, and detectors. Resolution maps for flow rate and temperature relationships of poorly resolved peak pairs for 5%-phenyl methyl silicone and 7%-cyanopropyl 7%-phenyl methyl silicone capillary columns are presented. Resolution of target pesticides on the 5%-phenyl methyl silicone column was much more sensitive to changes in flow and temperature-ramp rates than was the 7%-cyanopropyl 7%-phenyl methyl silicone column. Optimal conditions resulted in a run time of approximately 20 min.
    Additional Material: 11 Ill.
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  • 37
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    Journal of High Resolution Chromatography 14 (1991), S. 357-360 
    ISSN: 0935-6304
    Keywords: Static headspace analysis ; Gas chromatography ; Isobaric headspace extraction ; MHE method ; Distribution coefficient ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
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  • 38
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    Journal of High Resolution Chromatography 14 (1991), S. 123-125 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Column technology ; LC-like packed capillary columns ; Hydrocarbons ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Capillary columns of 0.3-0.35 mm internal diameter and 0.3-7.7 m length, packed with 3 to 30 μm octadecylsilica stationary phases as used for liquid chromatography, were applied to gas chromatographic separation of low boiling hydrocarbons. Van Deemter plots for these columns showed the optimum column efficiency to occur at linear velocities of 4-5 cm/s. A short column was applied to the rapid separation of components of a natural gas and impurities in standard gases, while a long column was applied to the separation of complex mixtures.
    Additional Material: 5 Ill.
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  • 39
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    Journal of High Resolution Chromatography 14 (1991), S. 225-229 
    ISSN: 0935-6304
    Keywords: FTIR spectrometry ; Gas chromatography ; Supercritical fluid chromatography ; Liquid chromatography ; Trace Identification ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The results described in this paper demonstrate that Identifiable FTIR spectra of components separated by gas, supercritical fluid, and liquid chromatography can be measured in real time using a common approach. The sensitivity of each Interface is comparable with that obtained by interfacing the corresponding technique with a bench-top mass spectrometer. The combination of these two spectroscopic techniques should lead to an even more powerful means of Identification of volatile, semi-volatile, and non-volatile components of mixtures.
    Additional Material: 6 Ill.
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  • 40
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Solid phase extraction ; Structure-type separation ; Polycyclic aromatic hydrocarbons (PAHs) ; Diesel fuel ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simple and effective solid phase extraction (SPE) method using silica gel micro glass columns has been developed for the separation of diesel fuel into groups of aliphatic, and mono-, di- and polyaromatic hydrocarbons. It is based on a stepwise gradient of dichloromethane in n-pentane. The resulting fractions were analyzed by capillary gas chromatography with a flame ionization detector and coupled gas chromatography-mass spectrometry.Commercially available standards, and retention indices and mass spectra were used for identification of individual aromatic compounds. The principal polycyclic aromatic hydrocarbons (PAHs) in diesel fuel are naphthalene, biphenyl, fluorene, phen-anthrene and their alkylated derivatives. Sulfur-containing PAHs are mainly represented by methyl-substituted dibenzo-thiophenes.
    Additional Material: 4 Ill.
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  • 41
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    Journal of High Resolution Chromatography 14 (1991), S. 143-146 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Polymeric liquid crystal stationary phase ; Polysiloxane ; PCDD ; PCDF ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A newly developed side chain liquid crystal polysiloxane has been investigated as a stationary phase for the isomer-specific analysis of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans substituted at positions 2, 3, 7, and 8. The retention times from the chromatograms of a standard solution containing all PCDD and PCDF isomers were compared with those from solutions containing only those tetra- to octa-chlorinated compounds substituted at positions 2, 3, 7, and 8. In general, PCDDs substituted at positions 2, 3, 7, and 8 eluted later than most other isomers of the same congener group. The separations obtained on this stationary phase were compared with those obtained elsewhere using a commercially available product.
    Additional Material: 4 Ill.
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  • 42
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Retention index standards ; McReynolds constants ; Stationary phase selectivity ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 43
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    Journal of High Resolution Chromatography 14 (1991), S. 383-387 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary columns in series ; Volatile organic compounds ; Ambient air ; Alveolar air ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Analysis of volatile organic compounds in air samples requires high resolution capillary gas chromatography. When the sample contains both polar and non-polar compounds, use of only one type of stationary phase can be unsuitable if it leads to the preferential separation of one kind of component having the same polarity at the expense of the separation of other classes of component.This paper describes the coupling of fused silica capillary columns of different polarity and length in order to achieve the separation of such complex mixtures. The combination is evaluated with a 42 component standard mixture and then applied to various atmospheric air samples and alveolar air of exposed subjects to demonstrate the capabilities of the complete sampling and separation technique.
    Additional Material: 5 Ill.
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  • 44
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    Journal of High Resolution Chromatography 14 (1991), S. 587-589 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Headspace analysis ; Mass spectrometry ; Organic solvents ; Printing ink ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Static headspace analysis by gas chromatography has been found to be a suitable method for the analysis of organic solvents in printing inks. Experimental conditions for the analysis have been optimized, and the accuracy and relative standard deviation of the method has been determined. The solvent content of 29 printing inks has been measured.
    Additional Material: 2 Tab.
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  • 45
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    Journal of High Resolution Chromatography 14 (1991), S. 621-625 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Dynamic headspace analysis ; Thermodesorption ; Flavor analysis ; Cheese ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The performance of two commercially available systems employing dynamic headspace techniques for collection, enrichment, and injection of volatile compounds has been compared by GC analysis of test mixtures and dairy products. For technical reasons, it has not been possible to crate identical sorbent materials for both kinds of trap were not available, the most similar adsorbent available were chosen. The total quantity of volatile compounds from a test mixture at the column head was calculated using a theoretical model which enables comparable working conditions to be obtained. Under these circumstances special attention was paid to the repeatability of the data obtained from a test mixture in order to ensure reliable results in quantitative analysis. Significant differences in repeatability between the two systems seemed to originate from their distinctly different technical designs.A qualitative comparison of the systems has been performed using a sample of Swiss cheese. On the basis of the results obtained the systems have been dedicated to different applications in the laboratory of the FAM.
    Additional Material: 4 Ill.
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  • 46
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Comparative study ; Liquid crystalline stationary phases ; Polyester stationary phases ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two new categories of stationary phase have been studied: liquid crystals and polyesters. The liquid crystals were p,p′-azoxyphenetol, p(n-hexyloxy)phenyl-p′-methoxy benzoate, and p-pentyloxy-p′-ethoxyazoxybenzene; and the polyester phases 1,4-butanediol succinate (LAC-860), ethylene glycol succinate (LAC-886), diethylene glycol succinate (LAC-738), diethylene glycol adipate (LAC-296), and neopentyl glycol adipate (LAC-769).Abnormal chromatographic behavior, has been observed: an increase in specific retention volumes and an improvement in the separation of normal, branched, and cycloparaffins, depending on their structures, at high temperatures within a specified range. This phenomenon is the opposite of the behavior of traditional stationary phases. From the chromatograms obtained, plots of log vg0 against 1/T, and differential thermal analysis it is concluded that this abnormal behavior may be attributed to the penetration of solutes through the ordered structure of the mesophase and the rod-like molecules of the polyesters. Furthermore, the chromatographic behavior of some of the polyester (LAC-series) stationary phases in respect of temperature changes is similar to that of the nematic mesophases.
    Additional Material: 8 Ill.
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  • 47
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    Journal of High Resolution Chromatography 14 (1991), S. 579-583 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Fused silica capillary column ; Cold on-column injection ; Amino acid analysis ; Liver ; Brain ; Rat ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A procedure is described for the quantitative determination of amino acids in hepatic and brain tissue samples from the rat. Because the presence of certain matrix components in the tissue material led to interference with chromatographic analysis they were removed by a prechromatographic “clean-up” step.Quantitative analysis of amino acids, as their N-heptafluorobutyryl iso-butyl ester derivatives, was achieved by high resolution gas chromatography on an apolar fused silica open tubular column. Reproducibility data from the complete procedure are presented; coefficients of variation for arginine and histidine in hepatic tissue varied between 7.1 and 10.1% whereas those for most other amino acids were better than 5%, with a mean recovery of 90%.
    Additional Material: 2 Ill.
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  • 48
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    International archives of occupational and environmental health 45 (1980), S. 153-161 
    ISSN: 1432-1246
    Keywords: Pentachlorophenol ; High-performance liquid chromatography ; Gas chromatography ; Biological monitoring ; Pentachlorphenol ; Hochdruck-Flüssigkeits-Chromatographie ; Gaschromatographie ; Biological monitoring
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Für die Bestimmung von freiem Pentachlorphenol in der Luft und im Blut wurden leistungsfähige chromatographische Routineverfahren ausgearbeitet. Für die Raumluftbestimmung wird Pentachlorphenol durch Einleiten von Luft in einer Vorlage angereichert und nach Aufarbeitung in freier Form durch Hochdruck-Flüssigkeits-Chromatographie quantitativ erfaßt. Alternativ kann die Analyse nach Derivatisierung durch Kapillar-Gaschromatographie erfolgen. Freies Pentachlorphenol im Vollblut wird nach Aufarbeitung und Derivatisierung durch Kapillar-Gaschromatographie in Verbindung mit dem Elektroneneinfang-Detektor quantitativ bestimmt. Bei den beschriebenen chromatographischen Methoden sind die Eichkurven über den angegebenen Konzentrationsbereich linear. Die gaschromatographische Trennung blieb über den gesamten Untersuchungszeitraum völlig reproduzierbar. Die problemlose Derivatisierung läßt die beschriebene gaschromatographische Methode in Verbindung mit einem automatischen Probengeber für das biological monitoring auch größerer Kollektive geeignet erscheinen.
    Notes: Summary Efficient chromatographic procedures for the determination of free pentachlorophenol in air and in blood have been developed. Free pentachlorophenol from the indoor environment is preconcentrated in an impinger. Following a simple extraction, it is detected by high performance liquid chromatography without derivatisation. An alternate method is capillary gas chromatography of a suitable derivative. Unchanged pentachlorophenol in whole blood is similarly derivatised and determined quantitatively by capillary gas chromatography using an electron capture detector. The calibration curves of the described chromatographic methods were linear within the specified concentration range. Reproducibility of gas chromatographic separation remained unchanged during the whole research period. Owing to its relative simplicity, the described gas chromatographic method is advantageous for the biological monitoring of large collectives.
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  • 49
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    Archives of toxicology 44 (1980), S. 291-297 
    ISSN: 1432-0738
    Keywords: Tetrodotoxin ; 2-Amino-6-hydroxymethyl-8-hydroxyquinazoline ; (C9-base) ; Gas chromatography ; Mass spectrometry ; Autopsy material
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Eine gaschromatographische Methode zum Nachweis von Tetrodotoxin im Obduktionsmaterial wird beschrieben. Das Derivat (2-Amino-6-hydroxymethyl-8-hydroxychinazolin, C9-Base), das sich durch die Einwirkung der Alkalilauge auf Tetrodotoxin gewinnen ließ, wurde schließlich durch Gaschromatographic nachgewiesen. Die Massenspektren der trimethylsilyerten C9-Base werden neben den Ergebnissen der gaschromatographischen Untersuchung von acht tödlichen Intoxikationsfällen angegeben.
    Notes: Abstract A gas Chromatographic method for the detection of tetrodotoxin in autopsy material is described. The derivative (2-amino-6-hydroxymethyl-8-hydroxyquinazoline, C9-base), which was obtained from tetrodotoxin by alkali treatment, was finally detected by gas chromatography. The mass spectra of the trimethylsilylated (TMS) C9-base are presented together with the result of a gas Chromatographic investigation of 8 cases of fatal intoxication.
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  • 50
    ISSN: 1432-1076
    Keywords: Phenylketonuria ; Phenylpyruvic acid ; Phenylacetates ; Gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract There is a steady and nonlinear relationship between the levels of both phenylpyruvic acid (PPA) and o-hydroxyphenylacetic acid (oOPAA) in urine and the plasma levels of phenylalanine (phe) in children more than two years of age with phenylketonuria (PKU). If phe levels in blood rise above 0.35 mM (5.8 mg/100 ml) both aromatic acids are found regularly in urine. Typically, urinary concentrations of PPA are about 5 times higher than those of oOPAA. This report is based on the analysis of 94 samples from 51 children, on or off diet.
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  • 51
    ISSN: 1432-2048
    Keywords: Boron ; Foliar nutrition ; Nuclear reactions ; Transport (boron) ; Trifolium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The growth of white clover (Trifolium repens L.) is severely inhibited by boron starvation, but a foliar treatment with boric acid can transitorily alleviate the deficiency symptoms. The 10B(n ,α)7 Li nuclear reaction has been used to study boron transport in the plant after foliar application. More than 98% of the boron supplied remained at the point where it was applied to the leaves, and less than 2% was useful to the growth of the treated plant. This small “efficient” portion of boron was quite mobile. It was distributed to the different parts of the plant, then was transferred from the oldest parts to the newly formed leaves. Physiological and agronomical implications of these data are discussed.
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  • 52
    ISSN: 1432-0878
    Keywords: Preputial glands ; Nude mice ; Ultrastructure ; Gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The preputial glands of male nude (nu/nu) mice were analyzed by a combination of electron microscopy and gas chromatography to determine whether or not they are affected, like developing hairs and nails, by the nu/nu genotype. Results of the analyses revealed no differences between the glands of nude and normal male mice in either their ultrastructural characteristics or lipid secretory products.
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  • 53
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    Chromatographia 13 (1980), S. 203-206 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Carrier gas purity ; Sample stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The amount of oxygen which may be present in the gas volume corresponding to a peak is investigated and compared to the sample amounts. It is shown that even with high purity carrier gases one may have a significant excess of oxygen present at low sample amounts. Attention is drawn to the possibility of impurity build-up by diffusion e.g. through the septum.
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  • 54
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    Chromatographia 13 (1980), S. 263-270 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Metal complexes ; Enantiomers ; Isotopic composition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The high selectivity of complexation gas chromatography has been employed for enantiomer resolution and isotope separation. Thus, a chiral olefin, 3-methylcyclopentene, has been resolved analytically on optically active dicarbonyl-rhodium(I)-3-trifluoroacetyl-1R-camphorate in squalane. The deuterated ethylenes C2H4−nDn have been separated on the same rhodium(I)-containing stationary phase. The chiral aliphatic oxiranes epoxypropane andtrans-2,3-epoxybutane have been resolved on optically active nickel(II)-bis-3-trifluoroacetyl-1R-camphorate in squalane.
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  • 55
    ISSN: 1612-1112
    Keywords: Gas chromatography ; On-column abstraction ; Aliphatic aldehydes ; Amine antioxidants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The selective on-column abstraction of aliphatic aldehydes by gas chromatographic stationary phases containing N-iso-propyl N′-phenyl-p-phenylenediamine is described.
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  • 56
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    Chromatographia 13 (1980), S. 35-39 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Nitromethane ; Nitroalkanes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Impurities in commercially available nitromethane have been determined by gas-liquid chromatography using six different column packings. Besides nitromethane, 1-nitropropane, 2-nitropropane, acetonitrile, methanol, small amounts of ethanol and acetaldehyde have been detected. The presence of formaldehyde, ethyl acetate and acetone is probable. Mixtures containing comparable amounts of the four nitroalkanes could be separated on all columns, but plots of logarithms of the retention times vs. carbon number or boiling points of the nitroalkanes or column temperatures were linear only in case of columns packed with Porapak R and Q.
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  • 57
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    Chromatographia 13 (1980), S. 686-692 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Micropacked columns in GC ; Microparticles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Porous silica microparticles designed for modern liquid chromatography have proven effective in gas chromatography. Columns of 35–50 cm gave plate heights as low as 3.3 particle diameters and speeds of 2400 theoretical plates per second or 500 effective theoretical plates per second. Inlet pressures up to 70 atmospheres were required using hydrogen as carrier gas. The particles as received were too retentive for fast chromatography and gave asymmetric peaks. A coating of fluorosilicone oil overcame both problems. Other coatings were less effective. Bonded phases proved less satisfactory on both counts and also gave substantially less efficient columns and greater flow resistance. Column efficiency and flow resistance were sharply dependent on physical properties of the particles. The most efficient packing was clearly spherical particles of 5–10 μm diameter with narrow size distribution, pore diamters about 50 nm, BET surface areas of 25–50 m2/g and surfaces modified with trifluoropropyl silicone. A six-component hydrocarbon sample was separated in 33 s with a resolution of 4 for the most difficult pair and in 2.6 s with a minimal resolution. Performance was limited by end effects and by available pressure so that much better performance can be expected from longer columns and higher pressures.
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  • 58
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    Chromatographia 13 (1980), S. 752-754 
    ISSN: 1612-1112
    Keywords: Xylenol isomers ; Gas chromatography ; Polyols and polyethers as stationary phase ; Hydrogen bonding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Xylenol isomers can be resolved on most polyols (sugars or sugar alcohols) and polyethers (polyethylene glycol or polypropylene glycol) with hydrogen-bonding interaction. They are separated on vinical polyols which have more hydroxy hydrogen than tetrol, and even on vicinal triol when its hydroxy hydrogen is acidic (stronger proton donor). The stronger is the hydrogen bonding interaction between xylenols and the liquid phase, the better is the separation of 2,4- and 2,5-xylenol, and the poorer the separation of 2,4-and 2,3-xylenol.
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  • 59
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    Chromatographia 13 (1980), S. 651-660 
    ISSN: 1612-1112
    Keywords: Capillary columns, glass ; Gas chromatography ; Column preparation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Glass capillary column chromatography is the most rapidly growing part of gas chromatography. There are many complex new analytical tasks and they require special capillary columns. Fortunately there is a wide range of column preparation methods available, and they make the preparation of glass capillary columns a more varied job than that of packed columns. In this paper these methods are reviewed and suggestions are given for making task-oriented columns.
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  • 60
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    Chromatographia 13 (1980), S. 73-84 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Gas hold-up time ; Dead time
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The two approaches used for the calculation of the gas hold-up time and thus, the adjusted retention time are outlined, first for the restricted case when the carbon numbers of the three homologues used for the calculation are evenly spaced (c3−c2=c2−c1) and then, for the general case when (c3−c2) differs from (c2−c1). The basic difference in the philosophy of the two approaches is shown.
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  • 61
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Column characterization ; Oxidation ; Stationary phases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The on-column oxidation of hydrocarbons commonly used as stationary phases in column characterization is investigated. In each case significant shifts of retention are observed, which may be negative or positive depending upon the polarity of the test solutes and the adsorptivity of the support material. In order to reduce the consequent uncertainties in the Rohrschneider [1] and McReynolds [2] polarity values, a new method of column characterization is proposed. The applicability of the new method is illustrated by a consideration of a range of silicone liquid phases.
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  • 62
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    Chromatographia 13 (1980), S. 207-208 
    ISSN: 1612-1112
    Keywords: Trace determination ; Hydrogen chloride ; Ethylene oxide ; Gas chromatography ; Chlorinated solvents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is described for the determination of small quantities of hydrochloric acid in two chlorinated organic solvents (CHCl3 and CCl4). An excess of gaseous ethylene oxide is added to a liquid sample; the 2-chloroethanol formed is then analyzed by gas chromatography. The procedure is simpler and more sensitive in comparison with other conventional methods. It can be modified for other organic solvents.
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  • 63
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    Chromatographia 13 (1980), S. 567-571 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Helium detector
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Four main factors which determine the shape and the polarity of the helium detector signal are discussed. All possible responses of this detector, both in elution and in vacancy chromatography, are presented and special attention is drawn to the intermediate region. The idea of ionization vacancy is introduced for the specific case of two components which are unresolved by the column and to which the detector responds with different sensitivity.
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  • 64
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    Chromatographia 13 (1980), S. 574-575 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Xylenol isomers ; Sugar derivatives as liquid phases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Adenosine, guanosine and inosine used as liquid phases in gas chromatography permits the separation of all six xylenol isomers.
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  • 65
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    Chromatographia 13 (1980), S. 61-67 
    ISSN: 1612-1112
    Keywords: Optimization ; Carrier gas velocity ; Gas chromatography ; Influence of temperature on optimum velocity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Zusammenfassung Die Wahl der mittleren, linearen Trägergasgeschwindigkeit bei der Analyse von Mehrkomponentengemischen unter isothermen und temperaturprogrammierten Bedingungen wird diskutiert. Es wird gezeigt, daß stets eine Trägergasgeschwindigkeit gewählt werden sollte, die mindestens gleich, besser jedoch höher ist, als die optimale Gasgeschwindigkeit für den ersten Peak, gemessen bei der Starttemperatur (Temperaturprogramm) oder bei der eingestellten Ofentemperatur (isotherme Fahrweise).
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  • 66
    ISSN: 1612-1112
    Keywords: Configuration ; Chiral phases ; Gas chromatography ; Isovaline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The D-(resp. R) configuration of isovaline (=2-ethylalanine) was proved for the peptide antibiotics antiamoebin, Tü 165 (CBS 382.62), stilbellin, samarosporin (=emerimicin IV), suzukacillin B (A), trichotoxin A-40 and A-50. This contradicts the previously reported L-configuration for isovaline in antiamoebin and emerimicin IV. The configuration was determined by GC of the N-trifluoroacetyl-isovaline n-propyl ester on glass capillary columns coated with the chiral stationary phase N-propionyl-L-valine tert.-butylamide polysiloxane (Chirasil Val). The D-configuration of the isovaline from trichotoxin A-40 was also established independently using GC of N-pentafluoro-propionyl-isovaline (+)-3-methyl-2-butyl esters on glass capillary columns coated with OV 17.
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  • 67
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    Journal of High Resolution Chromatography 3 (1980), S. 248-252 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Column loadability - overload phenomenon ; Non-classical approach to theory of loadability ; Effect on retention times, peak shape ; Effect of column length ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The usual concepts of the dynamics of an overloaded solute band fail to explain several phenomena such as the typical “leading-tail” shape and retention deviations exhibited by overloaded peaks, and why these defects are more commonly observed in short columns. These and other related deviations from theory can be rationalized by a non-classical approach to the overloading phenomenon.
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  • 68
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    Journal of High Resolution Chromatography 3 (1980), S. 286-290 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary ; Discrimination due to FID ; Effect of carrier gas flow changes on detector sensitivity ; Hydrogen as carrier gas ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The sensitivity of an FID may change when the carrier gas flow rate changes during a chromatographic run. Sample parts which are eluted at reduced FID sensitivity produce a reduced peak area, hence are discriminated as compared to other components. Sensitivity changes were studied for hydrogen as carrier gas. For the detector tested, differences in the carrier gas flow rates of 1 ml/min shifted the FID sensitivity by 1 to 5% (depending on the fuel gas supply). Thus the stability of the sensitivity is no longer ensured as soon as the carrier gas flow rate is changed manually or by an automatic programmer during an analysis. Sensitivity drifts may also occur during temperature programmed runs with a pressure regulated carrier gas supply since the gas flow through the capillary drops with increasing temperature. Such shifts in the response became noticeable as soon as relatively high carrier gas flow rates combined with long range temperature programmes were used. The typical patterns of such discriminations are shown, closing with a discussion on the possibilities for minimizing such undesired effects.
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  • 69
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    Journal of High Resolution Chromatography 3 (1980), S. 301-302 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Polychlorinated biphenyls ; Liquid crystal phase ; Choice of stationary phases for analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
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  • 70
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    Journal of High Resolution Chromatography 3 (1980), S. 351-352 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Injector ; Concentrator ; Electrically heated inlet ; Capillary columns ; Vapor sampler ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 71
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    Journal of High Resolution Chromatography 3 (1980), S. 537-544 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Chromatographic properties of glass surfaces ; Fluorad FC 431 ; Glass capillary GC of basic compounds ; Modification of glass surfaces ; Deactivation of glass surfaces ; Acid-base behaviour of GC columns ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: “Leaching” or “etching” by strong mineral acids seems to be a necessary pretreatment step for the most commonly used deactivation procedures of glass capillaries by reaction with either polyethylene glycol or silylation reagents. The acidic sites which are formed on the surface during this acid treatment cannot be completely removed by the subsequent deactivation process. This drawback can be overcome by performing the leaching with water vapour, resulting in an accumulation of cations at the surface and a decrease in the number of silanol groups. Capillaries of this type show excellent properties for the chromatography of strongly basic compounds. After the wash-out of the alkaline surface layer, the acidity of the support is suited for the chromatography of strongly basic as well as strongly acidic compounds. Due to a lack of reactive acidic sites, special deactivation procedures have to be applied to capillaries produced in this way.
    Additional Material: 5 Ill.
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  • 72
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    Journal of High Resolution Chromatography 3 (1980), S. 583-584 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; (Fused silica) capillary columns ; Intermediate test ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 73
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    Journal of High Resolution Chromatography 3 (1980), S. 87-88 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, wide-bore glass WCOT ; Fourier Transform Infrared/glass capillary GC on-the-fly ; Coupling successful ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By the use of a wide-bore WCOT capillary column, it was possible to obtain the first on-the-fly GC/FT-IR spectra with a WCOT column. This wide-bore WCOT column gave improved separation, as compared to a SCOT column, and yielded identifiable infrared spectra for a real sample.
    Additional Material: 2 Ill.
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  • 74
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    Journal of High Resolution Chromatography 3 (1980), S. 124-128 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Series-coupled chemically differing columns ; Fundamental studies on the properties for basic theory started ; Retention time and separation efficiency ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Basic expressions are derived for both the retention time and the effective separation factor in serially coupled GC columns. The retention time is determined by two main parameters. The first is the fractional time spent by an unretarded solute in each column which, in turn, is determined by the relative column lengths and flow velocities through each column. The second parameter is the relative mass distribution coefficient of a particular solute in each column; a variable that can be adjusted by changing the relative temperatures of the columns. The expression for the effective separation factor relates the measured separation factor for the series combination to the separation factors on the individual columns, the fractional time spent by an unretarded peak in each column, as well as the relative values of the mass distribution coefficients of a particular solute on the different columns.
    Additional Material: 5 Ill.
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  • 75
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Preparation of deactivated capillaries for routine analysis ; Easy deactivation and pretreatment steps described in detail ; Comparison of different modes given ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new surface pretreatment for the preparation of wall-coated open tubular (WCOT) glass capillary columns has been evaluated. This technique involves the application of a non-extractable layer of Superox™-4, a 4,000,000 MW polyethylene glycol, to the glass surface as a pretreatment and deactivation agent. Unlike other polyethylene glycols, Superox-4 is stable at high temperatures (〉 300°C) in the absence of oxygen, coats smoothly onto a bare glass surface and resists droplet formation. WCOT columns (SE-54, Carbowax 20M, and SP-2250) prepared using this technique are compared to columns prepared using a modified Grob [2,3] BaCO3 procedure. The Superox-4 pretreated columns were equal or superior in quality to the BaCO3 pretreated columns, based on the appearance of an activity standard and the effective theoretical plates (Neff) per meter. Chromatograms showing practical application of the WCOT columns prepared using both methods is given.
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  • 76
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    Journal of High Resolution Chromatography 3 (1980), S. 146-146 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Cold trap heating ; Thermal focussing ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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  • 77
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    Journal of High Resolution Chromatography 3 (1980), S. 302-302 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary ; Fitting silica capillary columns ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 78
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    Journal of High Resolution Chromatography 3 (1980), S. 309-310 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Amino-carboxylic acid ; Silylation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 79
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    Journal of High Resolution Chromatography 3 (1980), S. 299-300 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, WCOT glass ; Urea herbicides ; s-Triazines herbicides and metabolites ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The authors have shown that capillary columns are perfectly adequate for the separation of s-triazine herbicides and urea herbicides. The method presented remains adequate when the initial molecules are accompanied by some of their metabolites.
    Additional Material: 4 Ill.
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  • 80
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    Journal of High Resolution Chromatography 3 (1980), S. 326-332 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Column chromatography ; Run comparison with corrections for variations in injected sample sizes ; Chromatogram reconstruction on a graphics terminal ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The application of a Hewlett-Packard 3354 B Laboratory Automation System has been studied in order to compare a series of gas chromatographic analyses. A computer program has been designed for the chromatogram reconstruction of all valid sample runs from a system subsequence on an HP-2648 A graphics CRT terminal. The detector signals of the runs are compensated for variations in injected sample sizes when a number of conditions are met.
    Additional Material: 5 Ill.
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  • 81
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    Journal of High Resolution Chromatography 3 (1980), S. 359-360 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Mass spectrometry ; All-glass interface ; Fused silica ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 82
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    Journal of High Resolution Chromatography 3 (1980), S. 405-410 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Determination of adsorption ; Irreversible adsorption on glass columns made visible ; Fluorescent compound PMBF2 ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: PMBF2, a pyrromethene pigment, can be used in gas chromatography. Because of its fluorescence, adsorption sites on glass columns and connections can be traced in situ. The compound can be employed to check the inertness of glass surfaces after deactivation procedures. Some applications are described.
    Additional Material: 7 Ill.
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  • 83
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    Journal of High Resolution Chromatography 3 (1980), S. 411-412 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; All-glass T-joints and manifolds with small dead volume, production of ; Up to five-channel outlet splitter ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 84
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    Journal of High Resolution Chromatography 3 (1980), S. 525-526 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Static coating ; Filling the column by pressure, not by vacuum ; Device for filling by pressure ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
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  • 85
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    Journal of High Resolution Chromatography 3 (1980), S. 528-530 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Two-phase derivatization technique ; Yeast ; Splitless injection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 86
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    Journal of High Resolution Chromatography 3 (1980), S. 545-550 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, fused silica columns ; Selective detectors: TSD, ECD, FPD ; POTW sludge extracts ; Effluent splitter ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Combination of various GC detectors by using a Varian effluent splitter with glass capillary columns has been found to be a rapid procedure for profiling organics extracted from sludges and river sediments. The selectivity and the increased sensitivity of the thermionic nitrogen-phosphorus detector (TSD), the electron capture detector (ECD), and the flame photometric detector (FPD) over the flame ionization detectors (FID) or mass spectrometers allow the detection of compounds present at trace levels without need for extensive sample cleanup. Furthermore, the combination of two selective detectors may supplement the information with regard to the chemical functionalities required for structure elucidation.
    Additional Material: 3 Ill.
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  • 87
    ISSN: 0935-6304
    Keywords: Gas chromatography ; High performance liquid chromatography ; Theoretical basis of column chromatography in multicomponent separations ; Required value of peak resolution and accuracy of obtained, quantitative method ; Plate height of solute with capacity ratio equal to one or approaching to infinity ; Linearity between peak width and retention value ; High efficient GC columns ; HPLC small-bore column ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The point of our published papers since 1957 is reviewed. The relations between the required value of peak resolution, K1 (or R), and peak separation, K3 (eqn 9); K1 and relative accuracy of a peak height quantitative method, Ph (eqn. 10); K1 and relative accuracy of a peak area method, Pa, (eqn. 12) at different concentration ratios, φ, are derived. The final result in Table 2 shows a large influence of φ on the required value of K1.The approximately linear relation between peak width and retention value (eqn. 18) exists not only in GC. but also in HPLC. Plate height values H1 and H∞ for a solute with capacity ratio, k′, equal to unity or approaching infinity, respectively, are used to evaluate the column efficiency (eqn. 20). The measuring methods (eqn. 21,22,23) and parameters effecting on H1 and H∞ are given for GC packed column (eqn. 24), GC open tubular column (eqn. 25) and HPLC (eqn. 26). In the light of this, columns of high efficiency were developed. Some typical chromatograms for high speed analysis and separation of complex mixtures are given.
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  • 88
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    Journal of High Resolution Chromatography 3 (1980), S. 585-586 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass or fused silica ; Adsorptive and catalytic activity ; Distinction of effects ; Discussion of active sites ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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  • 89
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    Journal of High Resolution Chromatography 3 (1980), S. 89-90 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Histamine TMS derivatives, complete separation, 2 minutes ; NPD used for quantitation down to 20 pg ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complete separation of the TMS derivatives of histamine, 1-methyl histamine and 3-methyl histamine was achieved in two minutes in a 7 m × 0.25 mm column coated with SP 2250. Using NPD, histamine was detectable at levels as low as 20 pg. This offers a rapid, sensitive procedure with potential for clinical diagnosis and food analysis.
    Additional Material: 3 Ill.
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  • 90
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    Journal of High Resolution Chromatography 3 (1980), S. 107-114 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Two-dimensional GC ; Odour evaluation ; Fraction collection, heart-cutting and enrichment ; Applications, essential oil analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simple but effective GC approach to odour evaluation and fraction collection with capillary columns is described. An allglass device splits the column effluent, with one splitter arm going to an FID. For odour evaluation, the other splitter arm is led via teflon tubing to the nose. Off-line heart-cutting is carried out by collecting the split effluent on a glass capillary microtrap, the inner walls of which are coated with OV-101. This allows recovery of nanogram amounts of material. Multipass operation or repeated collection leads to preparative capillary GC for further spectroscopic investigation. These techniques do not involve sophisticated equipment or valves. Applications of this type of smell analysis, heart-cutting and enrichment in the analysis of Rhododendron fragrantissimum essential oil, black pepper essential oil and hop essential oil, illustrating the versatility of the systems, are presented.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 91
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 419-420 
    ISSN: 0935-6304
    Keywords: Meprobamate ; Overdose toxicology ; Plasma monitoring ; Gas chromatography ; High-pressure liquid chromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 92
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 447-451 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Organic gas phase cigarette smoke ; Volatile phase cigarette smoke ; Heated injection ; Nitrogen-phosphorous detector (NPD) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A heated injection system for a microprocessor-controlled GC has been developed for the (GC)2 analysis of the volatile phase of whole smoke of a cigarette. Effects of injection port temperature and the presence of a Cambridge filter pad are demonstrated. Chromatograms are shown for smoke samples with and without a Cambridge Filter with the sample valve oven at 25°, 165° and 205°C. The use of a flame ionization and a nitrogen-phosphorous detector is illustrated.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 93
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 521-522 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Computerized gas chromatography/mass spectrometry ; Capillary, OV-73 fused silica ; On-column injection ; Alkyl porphyrins ; Bis(trimethylsiloxy)silicon(IV) derivatives ; Fused silica as a GC/MS interface ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 94
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Electron capture detection ; Analysis of carboxylic acids and phenols in water ; Extractive alkylation ; Pentafluorobenzyl derivatives ; Steam condensate and domestic sewage effluent ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is presented for the simultaneous determination of a wide range of carboxylic acids and phenols in water. Extractive alkylation is used with the tetrabutylammonium ion as counter ion and pentafluorobenzylbromide as alkylating agent. Extracts are analyzed by glass capillary gas chromatography and electron capture detection. Using one ml of water sample, the detection limit lies in the range of 1-10 μg/l. Application has been made to the analysis of steam condensate and domestic sewage effluent.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 95
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 196-196 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Persilylation ; Barbiturates ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 96
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 461-470 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Series-coupled columns equipped with different stationary phases ; Independent temperature control of columns ; Retention time expressions ; Theory ; Selectivity control ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The promising technique of controlling chromatographic selectivity by the adjustment of individual column temperatures in systems of series-coupled columns is investigated by means of a general model incorporating the effects of temperature and mobile phase compressibility. Expressions are derived for the linear flow velocity, the effective partition coefficient and the retention time for a system of n columns assuming an ideal mobile phase gas, under conditions of constant overall pressure drop and neglect of the temperature dependence of the mobile phase viscosity. The results indicate the importance of thermodynamic parameters, relative to parameters influencing the linear flow velocity, in determining the effect of temperature on the chromatographic retention time. Numerical results are illustrated graphically for two-column systems which are discussed in greater detail. Switching of columns is also discussed and it is shown that even if thermodynamic contributions remain unchanged, non-thermodynamic contributions have a notice-able effect.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 97
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 21-22 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Deactivation ; Dynamic vapour-phase silylation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 98
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 86-86 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Recycle chromatography ; Multiple-pass chromatography ; Thermal focussing ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 99
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 195-195 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Columns, packed ; High resolution ; Packing apparatus ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 100
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 298-298 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Closing technique for static coating ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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