Evaluation of Retention Factors for Nine Solutes with Ionic Liquid Additives via Linear Solvation Energy Relationships

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.

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

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.

Chiral Separation of Ibuprofen by Supercritical Fluid Chromatography

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.

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

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.

Research Progress on Prevention and Treatment of Glucolipid Metabolic Disease with Integrated Traditional Chinese and Western Medicine

Hyperlipidemia, type 2 diabetes mellitus, nonalcoholic fatty liver and many other metabolic disorder are frequently co-existing in patients. In addition, these diseases are closely related in pathophysiological settings. However, increasing of the disease incidence, lacking of comprehensive prevention and control measurements against the key pathology point concomitant occurrence with the pattem of the single disease, single target therapy, that is leading therapeutic strategy for these metabolic disorders in the setting of Western medicine （WM）. On the basis of the combination of the advantages of integrated Chinese medicine （CM） and WM, with unified understanding of such diseases, the new concept of glucolipid metabolic disease （GLMD） is introduced. In this new concept, disorders in glucose and lipid metabolism are recognized as the key trigger and major driving force for the progress of GLMD. The key points of pathology included dysfunction of neuronal-endocrine-immune system,insulin resistance, oxidative stress, inflammation and intestinal flora imbalance. In the core pathogenic perspective of CM, it can be explained as ＂Gan （Liver） Shi Shu Xie＂ （dysfunction of Gan in metabolism and emotion regulation） that will lead to the occurence/production of endogenous dampness and phlegm, blood stasis and turbid. This leads to the new concept of ＂Liver-based regulatory system for metabolic homeostasis＂ to be introduced further. The comprehensive prevention and control strategy ＂Tiao Gan Qi Shu Hua Zhuo＂ （modulating Gan, trigging key metabolic system to resolve pathogenic factors such as phlegm retention and dampness）. Its representative formula Fufang Zhenzhu Tiaozhi Capsule （复方贞术调脂胶囊） is innovated under such rationales. Comment for some commonly-used CM GLMD therapeutic drugs was presented. High-level evidence-based and epidemiological and mechanism studies should be carded out to further interpret and explain of the scientific connotation of GLMD.