ISSN:0935-6304    

DOI:10.1002/jhrc.1240150402

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe scope of the principal techniques employed for the analysis of hydrocarbon mixtures is discussed, with emphasis on the analysis of one and two ring aromatic compounds by single column capillary gas chromatography. The paper considers both the column and the selection of the temperature regime (isothermal and temperature programmed). Much space is devoted to the characterization of the compounds by means of retention data.

ISSN:0935-6304    

DOI:10.1002/jhrc.1240150403

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

年代:1992

数据来源: WILEY

摘要:

AbstractReversed phase HPLC with short wavelength UV detection is a useful alternative to conventional separation systems, with RI detection, for the analysis of the triacylglycerols of highly unsaturated vegetable oils, including γ‐linolenic acid‐containing oils and technical drying oils.γ‐Linolenic acid‐containing triacylglycerols can be identified and separated from their α‐linolenic analogs. The triacylglycerol fingerprints obtained by this technique from many γ‐linolenic acid‐containing oils and technical oils are highly characteristic, as is apparent from chromatograms obtained from the seed oils ofOenothera biennis, Borago officinalis, Ribes nigrum, Primula florindae, andSapium sebiferum. Characteristic peak area ratios aid the identification of these oils, and estolide peaks are seen inSapiumseed kernel oils.The high detector response for triacylglycerols containing linoleate and/or linolenate residues may present additional advantages,e.g.in the detection of such triacylglyce

ISSN:0935-6304    

DOI:10.1002/jhrc.1240150404

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

年代:1992

数据来源: WILEY

摘要:

AbstractSimulated distillation boiling range distributions have been compared for high boiling petroleum wax samples using high temperature gas chromatography and supercritical fluid chromatography. Midpoint (50 % off) temperature differences were small, and average differences between the two types of analyses were less than 6° Details of optimization of the HTGC and SFC systems and injection techniques used are reported

ISSN:0935-6304    

DOI:10.1002/jhrc.1240150405

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe molecular emission of heteroelements such as phosphorus and sulfur is the basis of the selective response of the flame photometric detector. The behavior of the FPD towards phosphorus compounds has been studied and design improvements sought with regard to burner configuration and temperature distribution. The possibility of differentiating between compounds containing phosphorus atoms and those containing both phosphorus and sulfur atoms has also been examined.Detection limits and response characteristics have been reported for organophosphorus pesticide residues in samples of natural origin

ISSN:0935-6304    

DOI:10.1002/jhrc.1240150406

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe applicability of supercritical CO2extraction as a quantitative method for recovery of a hypolipidemic drug from an animal food matrix has been evaluated. Off‐line extraction with solid phase trapping and solvent rinsing has been utilized. An optimized method for quantitative extraction of the pure drug was initially developed with high reproducibility. Three drug/rat feed matrices were examined. The as‐received “crystalline matrix” yielded the poorest reproducibility suggestive of a heterogeneous matrix. A laboratory‐prepared crystalline drug/feed matrix and a matrix prepared by spiking the animal feed with a solution of the drug gave ten‐fold better RSDs than the “crysta

ISSN:0935-6304    

DOI:10.1002/jhrc.1240150407

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

年代:1992

数据来源: WILEY

摘要:

AbstractGas chromatographic procedures are described for the determination of carboxylic acids and chlorinated anilines in water samples.Propionic acid and 2,6‐difluorobenzoic acid in aqueous solution have been simultaneously alkylated and extracted by means of a continuous two‐phase reaction system, and then quantitated by on‐line coupled capillary gas chromatography; tetrahexyl‐ammonium hydrogen sulfate was used as phase transfer catalyst and pentafluorobenzyl bromide as reagent.A factorial design approach was used to optimize on‐line derivatization of aqueous propionic acid with regard to pH and concentration of phase transfer catalyst. Alkylation and extraction, under optimized conditions, followed by quantitation of the pentafluorobenzyl ester by flame ionization detection furnished a linear calibration for concentrations between 0.1 and 10 μg/ml. The relative standard deviation was 9–15 %.The continuous two‐phase reaction system was also used to determine (chlorinated) anilines present in water at concentrations of 0.1–1 μg/ml; pentafluorobenzoyl chloride was used as reagent and analysis was performed by capillary gas chromatography with flame ionization or electron capture detection. The on‐line acylation ofp‐chloroaniline was optimized with regard to pH, reagent concentration, and reaction time.The on‐line reaction system worked satisfactorily for both applications, although excess reagent caused some problems

ISSN:0935-6304    

DOI:10.1002/jhrc.1240150408

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

年代:1992

数据来源: WILEY

摘要:

AbstractRetention times of fifty one important chlorobiphenyl congeners have been determined on seven narrow bore GC columns coated with different stationary phases. The retention times of the chlorobiphenyls relative to tetrachloronaphthalene were plotted for different column combinations; the plots generated can be used to choose an optimum column combination for the multidimensional gas chromatographic separation of the chlorobiphenyls.

ISSN:0935-6304    

DOI:10.1002/jhrc.1240150409

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe use of high‐temperature‐stable, medium polarity glass capillary columns coated with immobilized PS‐090 (a 20 % diphenyl‐substituted, CH3O‐terminated polydimethylsiloxane) has made it possible to analyze routinely, and with good separation efficiency, high molecular weight compounds such as triglycerides and free base porphyrins. Cold on‐column injection was used throughout this work to avoid discrimination against involatile compounds, and disposable (fused silica) retention gaps were used to protect the column against contamination with involatile material. On‐column injection into narrow bore glass columns was achieved by using glass‐to‐silica connections to attach wider bore (0.2 mm i.d.) deactivated fused silica tubi

ISSN:0935-6304    

DOI:10.1002/jhrc.1240150410

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

年代:1992

数据来源: WILEY

摘要:

AbstractHigh resolution gas chromatography, with mass selective detection, has been used for the analysis of PCB on methyl 50 % octyl polysiloxane (SB 50 Octyl), methyl octadecyl polysiloxane, and a smectic polysiloxane (SB Smectic); and for the analysis of polychlorodibenzodioxins and polychlorodibenzofurans with 1 to 8 chlorine substituents on 100 % cyanopropyl siloxane (SP 2331), smectic polysiloxane (SB Smectic), a new polar stationary phase (DB‐Dioxin). The analysis has also been performed by column couplin

ISSN:0935-6304    

DOI:10.1002/jhrc.1240150411

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

年代:1992

数据来源: WILEY