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  • 11
    Digitale Medien
    Digitale Medien
    Quantitative analysis of disaturated lecithins in human plasma by ammonia chemical ionization mass spectrometry (1981)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 8 (1981), S. 503-505 
    Details
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Three physiologically important disaturated lecithins have been analyzed quantitatively as the acetate derivatives using a solids inlet probe and ammonia chemical ionization. Concentration independent response factors have been determined over a tenfold range that brackets human plasma levels. The results obtained serve as an independent corroboration of gas chromatographic analyses.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bms.1200081008
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  • 12
    Digitale Medien
    Digitale Medien
    Octafluorotoluene as a derivatizing agent for steroids in human plasma (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 16 (1988), S. 211-213 
    Details
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The use of octafluorotoluene (OFT) as a versatile gas chromatographic/mass spectrometric derivatizing agent for steroids containing alcoholic, phenolic or α,β-unsaturated keto functions, is described. Two distinct derivatizing schemes can be utilized, involving (method 1) a phase-transfer reaction, employing a two-phase system of CH2Cl2 and N NaOH with n-Bu4NHSO4 as catalyst (suitable for alcoholic and phenolic steroids) and (method 2) a reaction conducted in anhydrous dimethylformamide at 155°C with CsF as base (appropriate for α,β-unsaturated keto steroids). Perfluorotolyl (PFT) ethers and/or enol ethers have thus been generated. The electron impact spectra display abundant high-mass molecular ions where derivatization has occurred at a phenolic or enolic function. An extraction, derivatization and gas chromatographic/mass spectrometric scheme has been devised involving method 2 for the analysis of steroids in human plasma. A preliminary quantitative investigation of the levels of testosterone in plasma has been carried out employing these methods. The anomalously high level found is explained in terms of the presence in plasma of lipid-soluble derivatives of testosterone (probably fatty acid esters) which generate the testosterone bis-OFT derivative under the reaction conditions employed.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bms.1200160138
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  • 13
    Digitale Medien
    Digitale Medien
    Analysis of mercapturic acid conjugates of xenobiotic compounds using negative ionization and tandem mass spectrometryPresented in part at the 36th Annual Conference on Mass Spectrometry and Allied Topics, San Francisco, 1988. (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 22 (1993), S. 68-76 
    Details
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Mass spectra of mercapturic acid conjugates of two xenobiotic products of lipid peroxidation (trans-4-hydroxy-2-hexenal and trans-4-hydroxy-2-nonenal) as well as conjugates of 1,3-dichloropropene, styrene oxide, 1,2-naphthalene oxide and α-chlorotoluene were obtained using fast atom bombardment or negative chemical ionization. Fragmentation pathways were investigated using linked scan and mass-analyzed ion kinetic energy spectrometric techniques. Characteristics of the spectra obtained using different ionization and sample introduction techniques are compared. Deprotonated molecular ions of mercapturic acids gave simple daughter ion spectra, with the dominant mode of decomposition involving cleavage of C—S bonds giving a characteristic neutral loss of 129 Da Screening for mercapturates in urine samples was performed using neutral loss scanning and yielded limits of detection in the low nanogram per milliliter range. Quantitative analysis of the S-benzyl mercapturic acid at 1 p.p.b. in urine has been demonstrated using combined gas chromatography/electron capture mass spectrometry with d3-S-benzyl mercapturic acid as internal standard.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bms.1200220109
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  • 14
    Digitale Medien
    Digitale Medien
    Confirmation of oxytetracycline, tetracycline and chlortetracycline residues in milk by particle beam liquid chromatography/mass spectrometryThis work was presented in part at the 38th ASMS Conference on Mass Spectrometry and Allied Topics, Tucson, Arizona, June 1990. (1991)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 20 (1991), S. 789-795 
    Details
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A method using particle beam liquid chromatography/mass spectrometry was developed for the confirmation of oxytetracycline, tetracycline and chlortetracycline residues in bovine milk. This method is one of the first to apply particle beam technology to the confirmation of animal drug residues in food products for regulatory purposes. The milk is centrifuged, using molecular weight cut-off filters to remove components of 25 000 daltons and above from the milk. The filtrate is passed through a C-18 sample preparation cartridge which retains the tetracyclines. After the columns are washed with water, the tetracyclines are eluted with 0.1 M oxalic acid in methanol and concentrated. The compounds are separated on a Novapak C-18 column with a methanol-oxalic acid-acetonitrile mobile phase. Negative chemical ionization with selective ion monitoring is used to identify the tetracyclines. The procedure was used to confirm the presence of each tetracycline at 100 ng ml-1 in fortified and incurred milk samples.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bms.1200201208
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  • 15
    Digitale Medien
    Digitale Medien
    Preparation and testing of local polyester composites based on unsaturated polyesters as binder (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 31 (1986), S. 2705-2710 
    Details
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: A series of polymeric composites were prepared with sand/polyester ratio 92:8%. The sand used was local one. The polymeric composites were tested for their compressive strength, exterior volume, porosity, water uptake, specific gravity, volume of open pores and bulk density. The mechanical properties of these polymeric composites were within the range required for building bricks. No significant differences were observed between the polymeric composites made of glass sand and those from untreated sand except in exterior volume and compressive strength. Medium untreated sand was found to give better results in the mechanical properties.
    Zusätzliches Material: 5 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/app.1986.070310825
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  • 16
    Digitale Medien
    Digitale Medien
    Structure and properties of p-carboxysuccinanilic polyester resins (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 35 (1988), S. 75-83 
    Details
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Polyester resins were prepared by the reaction of p-carboxysuccinanilic acid ethyl ester with ethylene glycol and 1,4-butenediol. Also, unsaturated polyester resins were prepared by the copolymerization of p-carboxysuccinanilic acid ethyl ester and maleic anhydride with ethylene glycol, 1,6-hexanediol, 1,4-butenediol, and 2-butyne-1,4-diol. All the polyester resins and the copolyesters have been characterized and were found to cure with styrene, except those prepared in the absence of maleic anhydride. The properties of the cured products in the form of films were determined. Infrared and nuclear magnetic resonance (NMR) spectroscopy were used for both qualitative and quantitative analyses of the polyester resins and their hydrolyzate products after curing with styrene.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/app.1988.070350107
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  • 17
    Digitale Medien
    Digitale Medien
    Preparation by suspension polymerization of porous beads for enzyme immobilization (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 39 (1990), S. 169-177 
    Details
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Porous beads have been prepared by suspension polymerization of acrylic monomers and divinyl benzene in the presence of a porogen. The porosity varies greatly with the polymer composition, with the amount and type of porogen and with the conditions for the preparation. The enzyme binding capacity and activity has been determined for a lipase. The best results are found for crosslinked poly(methyl methacrylate) beads while other polyacrylates are less effective. Compositions based on poly(methacrylic acid) are not suitable for enzyme binding.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/app.1990.070390114
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  • 18
    Digitale Medien
    Digitale Medien
    Qualitative and quantitative high performance liquid chromatographic analysis of monoamine neurotransmitters and metabolites in cerebrospinal fluid and brain tissue using reductive electrochemical detection (1990)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 4 (1990), S. 215-220 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The application of reductive coulometric electrochemical detection for analysis of the monoamine neurotransmitters norepinephrine, dopamine, and serotonin and their common metabolites in brain and cerebrospinal fluid following separation by isocratic high performance liquid chromatography is described. The high sensitivity and screening capabilities of coulometric electrodes permits the accurate quantitation of as little as 3-5 pg of these compounds in tissue following a simple single step purification procedure. Moreover, comparison of peak height ratios obtained from analysis of authentic reference standards and tissue samples at selected multiple electrode potentials provides a straightforward means for qualitative evaluation of peak identification and purity during analysis of biological samples. The method is comparatively inexpensive and precise within and between day coefficients of variation for most compounds range from 2-5%. Thirty samples can be run in duplicate in a 24 h period.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130040509
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  • 19
    Digitale Medien
    Digitale Medien
    Solventogenesis in Clostridium acetobutylicum fermentations related to carboxylic acid and proton concentrations (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 32 (1988), S. 843-852 
    Details
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The mechanism primarily implicated in the solventogenesis process in batch fermentations of Clostridium acetobutylicum is examined in considerable detail. A variety of fermentations with or without pH control in the pH range of 3.7-6 have been carried out in order to examine which of a host of suspect parameters correlate with the initiation of solventogenesis. The parameters that did not correlate are the external (pH0) and intracellular (pHi) pH, and ΔpH, and the external or intracellular butyrate and acetate concentrations. Undissociated butyric acid (UBA) correlated well with the initiation of solventogenesis. A linear relationship between UBA and butanol concentrations was found at the onset of solventogenesis in all fermentations examined. The intercept of this linear relationship was 6-13mM UBA for the pH0 range of 3.7-5 and approximately zero for pH0 at or above 6. The required minimal UBA was interpreted as a dependency of the solventogenesis process on both H+ and butyrate concentrations. Undissociated acetic acid was found not to correlate with the initiation of solventogenesis. Addition of acetoacetate (AA) and propionate enhanced the effect of UBA on the solventogenesis process. The action of a nonmetabolizable (FCCP) and a metabolizable (AA) uncoupler on the ΔpH, pH0, pHi, and solventogenesis were also studied in order to gain further understanding of the solventogenesis mechanism.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bit.260320702
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  • 20
    Digitale Medien
    Digitale Medien
    Chemometric methods for process monitoring and high-performance controller design (1992)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 38 (1992), S. 1593-1608 
    Details
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A huge amount of data is collected by computer monitoring systems in the chemical process industry. Such tools as principal component analysis and partial least squares have been shown to be very effective in compressing this large volume of noisy correlated data into a subspace of much lower dimension than the original data set. Because most of what is eliminated is the collinearity of the original variables and the noise, the bulk of the information contained in the original data set is retained. The resulting low dimensional representation of the data set has been shown to be of great utility for process analysis and monitoring, as well as in selecting variables for control. These types of models can also be used directly in control system design. One way of approaching this is to use the loading matrices as compensators on the plant. Some advantages of using this approach as part of the overall control system design include automatic decoupling and efficient loop pairing, as well as natural handling of nonsquare systems and poorly conditioned systems.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/aic.690381010
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