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Prediction of liquid chromatography retention factors for α-branched phenylsulfonyl acetates using quantum chemical descriptors

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Journal of Environmental Sciences 2002年第2期14卷 151-155页

作者： LiuXH WuCD StateKeyLaboratoryofPollutionControlandResourceReuse DepartmentofEnvironmentalScienceSchooloftheEnvironmentNanjingUniversityNanjing210093China StateKeyLaboratoryofPollutionControlandResourceReuse

The logarithms of retention factors normalized to a hypothetical pure water eluent(log k w) were determined on a reversed phase high performance liquid chromatography(RP HPLC) column (Li Chrosorb RP 18 column) for 20 new α\|branched phenylsulfonyl acetates. The atomic charge method was applied to develop quantitative structure retention relationships(QSRRs). Among the available geometric and electronic descriptors, surface area (S), ovality (O), and the charge of carboxyl group(Q OC ) are significant. In the model, the contribution of surface area (S) is the greatest. The molecular mechanism of retention was demonstrated through the model. With the correlation coefficient ( r 2 adj , adjusted for degrees of freedom) of 0.964, the standard error of 0.164 and the F value of 170.39, the model has good predictive capacity.

关键词： phenylsulfonyl acetates quantum chemical descriptor quantitative structure retention relationships (QSRRs) retention factor

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Evaluation of retention factors for Nine Solutes with Ionic Liquid Additives via Linear Solvation Energy Relationships

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Chemical Research in Chinese Universities 2010年第4期26卷 532-536页

作者： ROW Kyung-Ho Department of Chemical Engineering Inha University

A linear solvation energy relationships（LSERs） model was used to examine the fundamental chemical interactions governing the retention of 9 organic compounds on a C18 column by means of reversed-phase high performance liquid cbromatography（RP-HPLC）. Three ionic liquids, 1-hexyl-3-methylimidazolium tetrafluoroborate （[Hmin][BF4]）, 1-butyl-3-methylimidazolium tetrafluoroborate（[Bmin][BF4]） and 1-octyl-3-methylimidazolium tetrafluoroborate（[OMIm][BF4]） as additives, were added to a methanol-water mobile phase. The effects of these three ionic liquids additives on the retention of nine organic compounds were investigated, and a comparison between the predicted and experimental retention factors was made via the LSERs model, which indicated that the LSERs model could be used to reproduce the experimental retention factors of the solutes under different mobile phase conditions. It is also a useful tool for modeling the interactions of the solutes between the stationary and mobile phases and evaluating the retention characteristics of HPLC.

关键词： retention factor Ionic liquid Additive Mobile phase Model

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Chiral Separation of Ibuprofen by Supercritical Fluid Chromatography

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Chinese Journal of Chemical Engineering 2005年第6期13卷 741-746页

作者： HAN Soonkoo ROW Kyungho Center for Advanced Bioseparation Technology and Department of Chemical Engineering Inha University253 Yonghyun-DongNam-KuIncheon 402-751South Korea

The separation method using chiral stationary phase （CSP） for the preparation of enantioselective compound was widely used. In this work, supercritical fluid chromatography（SFC） was proposed to resolve the chiral mixtures. To determine the optimum operating conditions for the chiral separation of the racemic ibuprofen, the retention factors and resolutions with the change in pressure, temperature and the content of IPA （%, by volume） in supercritical CO2 were investigated. Experiments showed that the retention factor decreased with the increase of pressure and decrease in temperature. The retention factor was also influenced by the content of IPA in mobile phase, as the content of IPA in the supercritical fluid increased, the retention factor decreased. The resolution of the enantiomers became worse with the increase of IPA in the supercritical fluid. Through optimizing the experimental conditions, a SFC procedure with 13MPa, 311.15K and 4% IPA in CO2 was obtained. The peak shape of the enantiomers was symmetric with supercritical fluid chromatography when compared to the asymmetric peak shape obtained by the conventional liquid chromatography. This work demonstrated that the developed supercritical fluid chromatography procedure was suitable for the chiral separation of ibuprofen enantiomers.

关键词： chiral separation ibuprofen retention factor resolution supercritical fluid chromatography

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Identification and Quantification of Monosaccharides in Aloe vera Gel by Acid and Enzymatic Hydrolysis and Wet Heat Treatment

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Food and Nutrition Sciences 2017年第8期8卷 840-853页

作者： Dianeli Madera Pina Carlos Hernán Herrera Méndez Lourdes Vargas y Vargas Herbert Loria Sunza Jorge Tamayo Cortez Research and Postgraduate Division Instituto Tecnológico de MéridaMéridaMexico Agroindustrial Engineering Department Campus Celaya-SalvatierraUniversidad de GuanajuatoSalvatierraMéxico

Aloe vera (Aloe barbadensis Miller) possesses curative and therapeutic properties attributed to the polysaccharides found in its tissue. This work aimed to study hydrolyzed (chemical and enzymatical) Aloe vera gel extracts using ultrafiltration membranes with a pore size of 0.22 micron (μm). Nine chemical treatments were achieved with H2SO4 and three wet heat treatments were carried out at a pressure of 1.2 lbf/in2 for 15 minutes;in both cases, three different concentrations of Aloe vera gel juice (AGJ) were used: 1.5%, 2.5% and 3.5% w/w. The concentrations of H2SO4 were 0.10%, 0.25% and 0.40% w/w. Chemical experiments are performed over a factorial 32 design and results were analyzed using SPSS software (version 17, SPSS Inc.), finding the one labeled T7 (15 ml of AGJ 3.5% with 15 ml of H2SO4 0.10% added) the best of them, as it leaded to 0.0446 mg/ml of liberated glucose. Among the three wet heat treatments, the one labeled TC3 (15 ml of AGJ 3.5% with 15 ml of H2O added) was the best-performing one, as it leaded to 0.292 mg/ml of liberated glucose. Furthermore, an enzymatic hydrolysis was carried out using Novozymes’ Pectinex? AR and Viscozyme?. Hydrolisis with both enzymes yield to better results than acid hydrolysis: in the treatment with Pectinex? AR, 3.282 mg/ml of liberated glucose were obtained and 3.302 mg/ml in the treatment with Viscozyme?. The hydrolyzed substances obtained by acid and enzymatic hydrolysis, as well as by wet heat treatment, were subsequently analyzed by thin layer chromatography (TLC), using glucose, galactose and arabinose 1000 ppm solutions as reference patterns. Among the treatments by H2SO4, the one labeled T4 obtained an Rf value of 50, the same as on the galactose reference pattern.

关键词： Carbohydrates Enzyme Mucilage Reducing Sugars retention factor

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