ISSN:0935-6304    

DOI:10.1002/jhrc.1240120702

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThis report describes a convenient means of reducing the complex matrix which is responsible for interference during gas chromatographic determination of amino acids in urine. The pre‐chromatographic clean‐up employs the principle of solid phase extraction using bonded silica incorporating cation exchange groups. This approach avoids the detrimental effects on amino acid recoveries associated with resin‐based cation exchangers. In spite of significant reduction in the complexity of chromatograms, only the high efficiency and resolving power offered by the analytical capillary column (e. g.fused silica open tubular, FSOT) is sufficient for quantitative and analysis of amino acids in urine. Reproducibility data from the complete procedure are determined, coefficients of variation (CV) for most amino acids being better than 5% with a mean recovery o

ISSN:0935-6304    

DOI:10.1002/jhrc.1240120703

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThe performance of a PTV injector operated in the solvent venting mode with Tenax in the glass insert was evaluated with synthetic mixtures containing 5 to 50 ng ofn‐alkanes, ethyl esters,n‐alcohols, and carboxylic acids.The influence of the sampled amount, the injected volume, and the nature of the solvent on accuracy and precision were studied.Coefficients of variation of relative (normalized) peak areas and absolute peak area ratios of each compound to the standard are of the order of

ISSN:0935-6304    

DOI:10.1002/jhrc.1240120704

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractNon‐aqueous reverse phase chromatography was used to optimize the separation of all‐trans‐α‐ and β‐carotenes and theircisisomers extracted from dried carrots. The technique can easily be applied to routine assays. Optimization was carried out by modifying the concentrations of methylene chloride and acetonitrile, and by studying the influence of temperature on the capacity factors and selectivity. The effect of the type of C 18 stationary phase bonding (mono‐ and polyfunctional) on separation was also examined. The need for polymeric bonding on the stationary phase is stressed for the realization of thetrans/cisisom

ISSN:0935-6304    

DOI:10.1002/jhrc.1240120705

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractConversion of disaccharide reducing units into the corresponding methoximes followed by their reduction with NaBH4CN to the corresponding deoxy(methoxyamino)alditol glycosides (RCH2‐NHOCH3) introduces a constitutional asymmetry in the sugar molecule. After methylation of the resulting compounds, cleavage of the glycosidic bonds is carried out by BF3‐ catalyzed methanolysis, affording permethylatedO‐methylglycosides and permethylated deoxy(methylmethoxyamino)alditols with a free −OH corresponding to the position of the glycosidic bond. Identification of the reducing moiety is achieved by GC‐FTIR and computerized retrieval of library FTI

ISSN:0935-6304    

DOI:10.1002/jhrc.1240120706

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240120707

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240120708

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240120709

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240120710

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240120711

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY