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111.
Summary The dependence of the capacity factor of polycyclic aromatic hydrocarbons on column temperature and on the density of the mobile phase in supercritical-fluid chromatography was investigated using carbon dioxide as the mobile phase. Logarithmic capacity factors of polycyclic aromatic hydrocarbons were obtained as a linear function of the reciprocal column temperature at a constant molar volume of carbon dioxide.The application of the Retention Prediction System to supercritical-fluid chromatography is demonstrated: one can predict the retention of polycyclic aromatic hydrocarbons using equations including column temperature, density and the physico-chemical properties of the solutes as the parameters. 相似文献
112.
K. Jinno T. Katoh M. Okamoto J. C. Fetzer W. R. Biggs 《Journal of separation science》1988,11(1):33-38
The retention behavior of condensed large polycyclic aromatic hydrocarbons has been investigated with diphenylsilica stationary phases in reversed-phase microcolumn liquid chromatography. The results were correlated with two parameters which indicate size and shape of the molecules. Since the resulting equation can be used for retention prediction of large polycyclic aromatic hydrocarbons, computer-assisted “standardless” identification is accomplished for “unknown” compounds contained in the standard. 相似文献
113.
Miniaturized sample preparation and separation methods for environmental and drug analyses. 总被引:3,自引:0,他引:3
Yoshihiro Saito Maki Kawazoe Motohiro Imaizumi Yoriko Morishima Yuji Nakao Kayo Hatano Makiko Hayashida Kiyokatsu Jinno 《Analytical sciences》2002,18(1):7-17
Miniaturized extraction and separation media have been successfully developed from precisely controlled technologies. In this article, recent developments in these high performance analytical methods, such as miniaturized sample preparation methods and the coupling of these techniques with microscale separation systems, have been reviewed, along with some applications to environmental and biological analysis. The advantage of the miniaturization is not only for the environmental compatibility but also for the developments of the high performance analytical systems. Down-sizing also makes it possible to investigate and introduce various compounds and materials as novel media (such as tailor-made materials and devices) in separation science. As a typical example of the novel miniaturized sample preparation system, the applications of fibrous materials for microcolumn liquid-phase separation methods are described. 相似文献
114.
Retention characteristics of fluorinated bonded silica phase in reversed-phase liquid chromatography
Summary Fluorinated bonded silica has been evaluated as a packing material in reversed-phase liquid chromatography (RPLC) with polycyclic aromatic hydrocarbons, chlorinated benzenes and substituted benzenes as sample probes. The bonded material is useful as a reversed-phase stationary phase and for polar compounds it offers a specific selectivity not found with octadecylsilica (ODS) phases. The phase also retains non-planar compounds more than planar molecules. The results can be explained by conformational differences between ODS and the fluorinated bonded phase by MM2 calculation. 相似文献
115.
K. Jinno T. Ibuki H. Lamparczyk M. Okamoto N. Tanaka J. C. Fetzer W. R. Biggs 《Chromatographia》1988,25(6):483-486
Summary The retention behavior of 15 peropyrene-type polycyclic aromatic hydrocarbons was investigated on various bonded stationary
phases in reversed-phase liquid chromatography. On diphenyl and naphthylethyl bonded phases, high correlations were obtained
between the molecular polarizability of solutes and their retention. However, very low or no correlations were found on various
octadecyl bonded phases. These facts are discussed by using the electrostatic interaction concept between the solutes and
the stationary phase. We conclude that these observations are due to two reasons: the difference in the degree of planarity
of polycyclic aromatic hydrocarbons and the high ability of planarity recognition of octadecyl bonded phases. 相似文献
116.
The main focus of this study was to explore the capability of native α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin and
their hydroxypropyl derivatives for host-guest interaction with 7,8-dimethoxyflavone, selected steroids (estetrol, estriol,
estradiol, estrone, testosterone, cortisone, hydrocortisone, progesterone and 17α-hydroxyprogesterone) and polycyclic aromatic
hydrocarbons (toluene, naphthalene, 1,8-dimethylnaphthalene, 1-acenaphthenol, acenaphthylene and acenaphthene) under reversed-phase
liquid-chromatography conditions. The study revealed that native cyclodextrins interact more efficiently with the analytes
investigated than do their hydroxypropyl counterparts. In the low-temperature region, enormously high ratios were observed
for polycyclic aromatic hydrocarbons, particularly 1,8-dimethylnaphthalene, acenaphthene and acenaphthylene chromatographed
on a β-cyclodextrin-modified mobile phase. In such a case, the retention times of the polycyclic aromatic hydrocarbons were
strongly reduced (e.g. from 127 to 1.2 min for 1,8-dimethylnaphthalene) and were close to the hold-up time of the high-performance
liquid chromatography (HPLC) system (0.7 min). Moreover, chiral separation of 1-acenaphthenol optical isomers was observed
and the elution order of the enantiomers was determined. Within the steroids group, strong interaction was observed for estradiol
and testosterone. The results of cluster analysis indicate that β-cyclodextrin as well as γ-cyclodextrin and its hydroxypropyl
derivative can be most effective mobile-phase additives under reversed-phase HPLC conditions for 3D-shape-recognition-driven
separation, performed at subambient and elevated temperatures, respectively. 相似文献
117.
118.
119.
K. Jinno K. Kawasaki M. Sato S. Amemiya T. Katoh 《Journal of Radioanalytical and Nuclear Chemistry》1983,76(1):139-149
The (pX, X) technique is a very reliable tool for trace element analysis when large amounts of a neighboring element are present.
This paper describes the experimentally determined detection limits of some available sources of GaAs, Ge and Zr, to evaluate
the utility of this technique. The theoretical detection limits calculated with a computer program are also described. 相似文献
120.
Solid-phase microextraction (SPME) is a solvent-free sample preparation technique using a thin coating attached to the surface of a fused silica-fiber as the extraction medium, which has been successfully applied to the analysis of a wide variety of compounds by coupling to gas chromatography (GC). In recent years, in-tube SPME using GC capillary column as the extraction medium has also been developed and coupled with liquid chromatography (LC) for the preconcentration of nonvolatile compounds. In this study, an on-line interface between the fiber-in-tube SPME and capillary electrophoresis (CE) has been developed, and the preconcentration and separation of four tricyclic antidepressant (TCA) drugs, amitriptyline, imipramine, nortriptyline, and desipramine, were performed with the hyphenated system. Under the optimized condition, a better extraction performance than conventional in-tube SPME was obtained, even the length of the extraction medium was much shorter. The results clearly indicated that the fiber was working effectively as an extraction medium. For the separation of these four TCAs, capillary electrophoretic separation with beta-cyclodextrin as the buffer additive has been employed and the application of the developed system to the analysis of complex sample mixtures in a biological matrix is also demonstrated. 相似文献