A three-phase solvent system was efficiently applied for high-speed counter-current chromatography to separate secondary metabolites with a wide range of hydrophobicity in Dicranostigma leptopodum. The three-phase solvent system of n-hexane/methyl tert-butyl ether/acetonitrile/0.5% triethylamine (2:2:3:2, v/v/v/v) was selected for high-speed counter-current chromatography separation. The separation was initiated by filling the column with a mixture of intermediate phase and lower phase as a stationary phase followed by elution with upper phase to separate the hydrophobic compounds. Then the mobile phase was switched to the intermediate phase to elute the moderately hydrophobic compounds, and finally the polar compounds still retained in the column were fractionated by eluting the column with the lower phase. In this research, 12 peaks were eluted out in one-step operation within 110 min, among them, eight compounds with acceptable purity were obtained and identified. The purities of β-sitosterol, protopine, allocryptopine, isocorydione, isocorydine, coptisine, berberrubine, and berberine were 94.7, 96.5, 97.9, 86.6, 98.9, 97.6, 95.7, and 92.8%, respectively.

A series of novel organic–inorganic hybrid porous materials were synthesized using the method of suspension polymerization. As content of oleic acid-coated TiO₂ introduced increased, the surface area, pore volume, and average pore diameter increased, and meantime macropores appeared. The adsorption efficiencies of the porous materials for (−)-epigallocatechin gallate (EGCG) and caffeine (CAF) were enhanced, due to synergistic effect of surface area, pore volume, average pore diameter, and several driving forces such as charge induced force, π–π stacking, and hydrogen bond. Adsorption kinetic analysis indicated that pseudo-second-order kinetics can reasonably depict the adsorption process, and intraparticle diffusion became more obvious after a contact time of 30 min. Adsorption isotherm analysis indicated Freundlich isotherm could be used to describe the adsorption process. Charge induced force, π–π stacking, hydrogen bond, and sieving effect of pores were the main driving forces for the adsorption of EGCG and CAF by the organic–inorganic hybrid porous materials. This study will open possibility of expanding number and types of porous materials and provide assistance in tailoring corresponding physical–chemical properties, according to specific analytes. POLYM. ENG. SCI., 55:2414–2422, 2015. © 2015 Society of Plastics Engineers

Three macroporous crosslinked poly(styrene-co-divinyl benzene) resins functionalized with p-phenylene diamine (PPDA), p-aminophenol, and p-aminobenzoic acid (PANB) groups were prepared, and their adsorption characteristics for the flavonoid constituents from the leaves of Olea europaea L were studied. The materials were characterized by Fourier transform infrared spectroscopy. The specific surface area and the pore size distribution of the adsorbents were calculated by the Brunauer–Emmett–Teller and Barrett-Joyner-Halenda methods. The results show that the materials had a faster adsorption rate and high adsorption capacities for flavonoids, and PPDA had the highest adsorption capacity in comparison with the others. The isotherms could be fitted by the Freundlich model, and the adsorption was an exothermic process. The adsorption kinetics could be characterized by the pseudo-second-order rate equation, and the initial stage was controlled by the intraparticle diffusion model. This study contributes to the remediation of adsorption for organic materials and active components of natural products and to the effects of different functional groups on adsorption mechanisms. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40188.

Under bubble with air compressor, macroporous adsorption resin was functionalized with amino and acetyl groups. The method avoided the fragmentation of the resin during modification. Alizarin yellow GG (AYGG) was used as an adsorbate to investigate adsorption kinetics of the modified resins. It showed that pseudofirst-order and pseudosecond-order kinetics cannot reasonably express the adsorption process. A new kinetic model, multi-layer adsorption model, showed much better fit to the adsorption kinetic data and corresponding kinetic parameters could predict adsorption mechanism. Meantime, AYGG can be easily recovered, and the resins can be regenerated. Due to π–π, electrostatic force and hydrogen bond interaction between the resin and carboxyl, phenolic hydroxyl, and azo groups of AYGG, the resin with amino group showed higher adsorption capacity than the other resins used in this study. Steric hindrance and decrease in electrostatic force were unfavorable for the enrichment of AYGG by the resin with acetyl group. Response surface model combining with central composite design was used to determine effects of pH and initial concentration on adsorption. It showed that a second-order polynomial regression model could reasonably express the experimental data and optimum adsorption conditions were obtained. The design provided an effective methodology to optimize an adsorption process. POLYM. ENG. SCI., 54:1960–1968, 2014. © 2013 Society of Plastics Engineers

High shear technique coupled with high-performance counter-current chromatography was successfully used for the extraction and online isolation of seven highly polar chemical constituents from the Brassica napusL. The lower phase of ethyl acetate–n-butanol–water (1:4:5, v:v:v) was used as both the high shear technique solvent and high-performance counter-current chromatography mobile phase. Seven compounds of 14.2 mg of uridine, 4.6 mg of xanthosine, 7.8 mg of guanosine, 5.3 mg of adenosine, 19.5 mg of kaempferol-3,4'-di-O-β-D-glucopyranoside, 17.7 mg of kaempferol-3-O-(2-O-β-D-glucopyranosy1)-β-D-glucopyranoside, and 25.7 mg of an unknown compound, with a high-performance liquid chromatography (HPLC) purity over 95.0%, were obtained in a one-step extraction-separation process within 130 min from 20.0 g of raw material of pollen of Brassica napusL. Moreover, the mode of elution–extrusion was employed for the separation of the last one compound. The isolated compounds were analyzed by HPLC, and the chemical structures of the compounds mentioned above were identified by UV and NMR. It is the first time to combine the high shear technique and high-performance counter-current chromatography for the online isolation of the nature products.

A series of macroporous adsorption resins (MARs) with novel structures is synthesized via Friedel–Crafts catalyzed reaction. The adsorption kinetics of the synthetic resins with respect to the purification effect is systematically investigated by means of the response surface methodology (RSM). The kinetic data cannot be fitted to the classical model because it does not take multicompartments and desorption rates into consideration. A new multicompartment louver-tide theory is thus developed considering that adsorption is an indefinite dynamic equilibrium process, which can be divided into innumerable ingredients with different desorption rates. This theory produces much better fits to the experimental data and provides a quantitative explanation with multicompartments and adsorption/desorption rates.

The aim of this paper is to characterize metabolism disorders in Kunming mice induced by S180 and H22 tumor cells. Metabolic fingerprint based on high performance liquid chromatography-diode array detector (HPLC-DAD) was developed to map the disturbed metabolic responses. In vivo testing of the antitumor activity of paclitaxel (Taxol) was carried out by inhibiting the growth of S180 and H22 tumor cells. Based on 27 common peaks, principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used to distinguish the abnormal from control and to find significant endogenous compounds (SECs) which have significant contributions to classification. The tumor growth inhibition ratios (TIRs) of Taxol groups were used to validate the predictive accuracies of the PLS-DA models. The predictive accuracies of PLS-DA models for S180 and H22 tumor model groups were 97.6 and 100%, respectively. Nine (S180) and seven (H22) SECs were discovered, including uric acid and cytidine. In addition, the correlations between relative tumor weights (RTWs) and chromatographic data for the SECs were significant (p < 0.05). Investigations on the stability and precision of the established metabolic fingerprints demonstrate that the experiment is well controlled and reliable. This work shows that the platform of HPLC-DAD coupled with chemometric methods provides a promising method for the study of metabolism disorders induced by tumor cells. Copyright © 2011 John Wiley & Sons, Ltd.