摘要:

AbstractThe purge and trap (P&T) method of analysis has been interfaced with fused silica capillary column gas chromatography. This interfacing has been accomplished without splitting the P&T trap desorption carrier gas. Thus, 100% of the purged compounds are transferred to the column. The analytes are cryofocussed on the column using whole column cryotrapping (WCC) at −80°C. The resulting P&T/WCC procedure is extremely well‐suited to the analysis of trace purgeable aqueous organic compounds. Samples and standards containing a variety of aromatic standard compounds were analyzed. The standards included benzene, toluene, ethylbenzene, xylenes, C3‐C4‐benzenes, and naphthalene, as well as three P&T internal standard compounds. Chromatographic peak widths were uniformly less than 6 s at the base and excellent precision was obtained in the relative retention time data for all compounds. The chromatogram of a groundwater sample contaminated with aromatic gasoline compounds is also presented. Since P&T/WCC works well with fused silica capillary columns, the full sensitivity and chromatographic efficiency of capillary gas chromatography is made available to P&T

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070902

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

年代:1984

数据来源: WILEY

摘要:

AbstractAs an alternative to acid pretreated UCON and FFAP capillaries for the analysis of wide‐boiling free fatty acid mixtures, OV‐1 : FFAP phase mixtures were used on high‐temperature silylated inert glass capillary columns. The HETP‐carrier gas velocity curves, peak asymmetry factors, coating efficiency, gas phase and stationary phase contributions to the mass transfer resistance were determined for various OV‐1 : FFAP ratios. Mixed‐phase capillaries showed optimum performance at a 2 : 1 OV‐1 : FFAP ratio. The thermal and long‐term stability of OV‐1‐stabilized FFAP columns surpassed those of the UCON and pure FFAP re

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070903

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

年代:1984

数据来源: WILEY

摘要:

AbstractSeveral ODS phases have been dynamically modified to act as ion exchangers. Their ability to separate inorganic ions has been evaluated. The different properties of these materials are demonstrated and a method for eliminating the appearance of the system peak is described.

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070904

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

年代:1984

数据来源: WILEY

摘要:

AbstractA method is described for the determination of 1‐nitropyrene in a diesel exhaust particulate extract by thin‐layer chromatography. 1‐Nitropyrene is determined as 1‐aminopyrene after prechromatographic reduction and isolation by solvent partition. The fluorescence response of 1‐aminopyrene is approximately 1000‐fold greater than that of 1‐nitropyrene. The poor fluorescence stability of 1‐aminopyrene on silica gel plates preventsin situdetection by scanning densitometry unless the plates are impregnated with a mixture of 2,6‐di‐tert‐butyl‐4‐methylphenol and Fomblin H‐Vac. A linear response from 1 to 150 ng of 1‐aminopyrene and a detection limit of 1.0 ng were obtained using the impregnated plates. For fourteen samples of a diesel exhaust particulate extract the concentration of 1‐nitropyrene was determined to be 165 μg/g with an RSD = 9.0%. No significant interferences were observed from other nitro‐ or aminopolycyclic aromati

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070905

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

年代:1984

数据来源: WILEY

摘要:

AbstractFor optimization of liquid chromatography separations, several approaches have been reported, among them the use of the hydrophobic fragmental constant, as proposed byRekker[1]. The fragmental constant is derived from the partition coefficients of various solutes between octanol and water and represents a summation of solubility parameters: van der Waals volume, π ‐ π interactions, hydrogen bonding,etc.With these constants the optimization of reversed phase mode liquid chromatography using octadecyl bonded silica gels as packing was feasible, although large error was found for the eluent with a high concentration of organic modifier or water. This is probably due to the heterogeneous solvation of the surface of the packings and to various solvent effects. In addition, when the acid dissociation constant was known, the retention times of aromatic acids in the ionic form were also predicted using the hydrophobic fragmental constant and the dissociation constant. By comparison of the previous data and a method proposed byPerrin et al.[2] it was possible to predict the dissociation constant of aromatic acids and optimize separation in reversed phase mode liquid chromatography using octadecyl bonded silica gels as packing. Furthermore, an equation for calculating the capacity ratios in a given pH eluent was proposed and the predicted and observed capacity ratios of aromatic acids in several eluents were examined in order to improve the above sys

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070906

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

年代:1984

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070907

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

年代:1984

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070908

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

年代:1984

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070909

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

年代:1984

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070910

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

年代:1984

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070911

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

年代:1984

数据来源: WILEY