Monolithic silica capillary column with coated cellulose tris(3,5-dimethylphenylcarbamate) for capillary electrochromatographic separation of enantiomers.

Monolithic silica capillary columns were prepared by a sol-gel process in fused-silica capillaries with an inner diameter of 50 microm and were modified by coating of cellulose tris(3,5-dimethylphenylcarbamate). Influences of the factors in the modification process on enantiomer separations were investigated. The prepared columns were used to perform enantiomer separations by CEC.

[Screening of antineoplastic components in Radix et Rhizoma Rhei using chromatographic fingerprints].

A new strategy for screening of antineoplastic components in the traditional Chinese medicine of Radix et Rhizoma Rhei has been developed using chromatographic fingerprints before and after metabolism by high performance liquid chromatography-mass spectrometry. The metabolizing method was established based on the in vitro metabolism by Sprague-Dawley (SD) rat liver homogenate. By means of the metabolism methods in vitro, the antineoplastic activity of the extracts, metabolites and components of Radix et Rhizoma Rhei were determined by microculture tetrazolium (MTT) assays in vitro.

Application of cross-linked beta-cyclodextrin polymer for adsorption of aromatic amino acids.

Beta-cyclodextrin (beta-CyD) was cross-linked by hexamethylene diisocyanate and the polymer was investigated for adsorption of aromatic amino acids (AAA) from phosphate buffer. High adsorption rates were observed at the beginning and the adsorption equilibrium was then gradually achieved in about 45 min. The adsorption of AAA decreased with the increase of initial concentration and also temperature.

[Experience in treating advanced prostate cancer with bladder outlet obstruction].

Background & Objective: The incidence and discovery rate of prostate cancer is increased in recent years; with advanced age and multiple organs dysfunction, the advanced prostate cancer patients have poor quality of life. This study was to explore suitable treatment for these patients.

Methods: A total of 80 advanced prostate cancer patients with bladder outlet obstruction were treated by transurethral electrovaporization of the prostate (TVP), plus castration and antiandrogen therapy.

Improved performance of comprehensive two-dimensional HPLC separation of traditional Chinese medicines by using a silica monolithic column and normalization of peak heights.

Performance of comprehensive two-dimensional liquid chromatography system is greatly improved than we reported previously by using a silica monolithic column as for the second dimensional separation. Due to the increase of the elution speed on the second dimensional monolithic column, the first dimensional column efficiency and analysis rate can be greatly improved as comparing with conventionally second dimensional column. The developed system was applied to analysis of methanol extraction of two umbelliferae herbs Ligusticum chuanxiong Hort.

Separation and detection of compounds in Honeysuckle by integration of ion-exchange chromatography fractionation with reversed-phase liquid chromatography-atmospheric pressure chemical ionization mass spectrometer and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis.

A hyphenated method for the isolation and identification of components in a traditional Chinese medicine of Honeysuckle was developed. Ion-exchange chromatography (IEC) was chosen for the fractionation of Honeysuckle extract, and then followed by concentration of all the fractions with rotary vacuum evaporator. Each of the enriched fractions was then further analyzed by reversed-phase liquid chromatography-atmospheric pressure chemical ionization mass spectrometer (RPLC-APCI/MS) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) with matrix of oxidized carbon nanotubes, respectively.

Capillary electrochromatographic separation of enantiomers under aqueous mobile phases on a covalently bonded cellulose derivative chiral stationary phase.

A chemically bonded cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phase (CSP) was prepared by a radical polymerization reaction. The prepared CSP was packed into fused-silica capillaries with inner diameter of 75 microm to perform enantiomer separations in CEC. The electrochromatographic behavior of the CSP was investigated.

Integration of ion-exchange chromatography fractionation with reversed-phase liquid chromatography-atmospheric pressure chemical ionization mass spectrometer and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for isolation and identification of compounds in Psoralea corylifolia.

An approach for the separation and identification of components in a traditional Chinese medicine Psoralea corylifolia was developed. Ion-exchange chromatography (IEC) was applied for the fractionation of P. corylifolia extract, and then followed by concentration of all the fractions with rotary vacuum evaporator.

Screening and analysis of bioactive compounds with biofingerprinting chromatogram analysis of traditional Chinese medicines targeting DNA by microdialysis/HPLC.

Biofingerprinting chromatogram analysis, which is defined as the comparison of fingerprinting chromatograms of the extract of traditional Chinese medicines (TCMs) before and after the interaction with biological systems (DNA, protein, cell, etc.), was proposed for screening and analysis of the multiple bioactive compounds in TCMs. A method of microdialysis sampling combined with high performance liquid chromatography (HPLC) was applied to the study of DNA-binding property for the extracts of TCMs.

Separation of compounds interacting with liposome membrane in combined prescription of traditional Chinese medicines with immobilized liposome chromatography.

Immobilized liposome chromatography (ILC), the stationary phase of which has been regarded as a mimic biomembranes system was used to separate and analyze compounds interacting with liposome membrane in Danggui Buxue decoction, a combined prescription of traditional Chinese medicines (CPTCMs), and its compositions Radix Astragli and Radix Angelica Sinensis. More than 10 main peaks in the extract of Danggui Buxue decoction were resolved on the ILC column, suggesting that more than 10 components in the prescription have significant retention on ILC column. Ligustilide, astragaloside IV and formononetin, three main bioactive ingredients in Danggui Buxue decoction, were found to have relatively significant, while ferulic acid, another bioactive ingredient in the prescription, relatively weak retention on ILC column.

[Applications of two-dimensional liquid chromatography coupled to mass spectrometry for the separation and identification of compounds in ginkgo biloba extracts].

A comprehensive two-dimensional liquid chromatographic separation system based on the combination of an immobilized liposome chromatographic (ILC) column and an ODS column was developed for the separation of components in Ginkgo biloba, a traditional Chinese medicine. Two columns were coupled by a two-position, eight-port valve equipped with two storage loops, and the system was controlled by a computer. The effluent was detected both by a diode array detector and by an atmospheric pressure chemical ionization (APCI) mass spectrometer.

[Preparation of covalently bonded cellulose tris (4-methylbenzoate) derivative chiral stationary phases through a polymerization reaction].

Cellulose tris (4-methylbenzoate) derivatives (CTMB) having methacryloyl groups were synthesized with regio-selective or nonselective procedures, and were immobilized on gamma-methacrylatepropylated silica (gamma-MAPS) through a polymerization reaction. The obtained chiral stationary phases ( CSPs) were evaluated by high performance liquid chromatographic (HPLC) resolution of 9 racemates (3-butyl-phthalide, ketoprofen, trans-stilbene oxide, benzoin, benzoin analogue, Tröger' s base, warfarin, 4,4'-dimethoxy-5,6,5',6'-dimethylenedioxy-biphenyl-2,2'-dicarboxylate and 4,4'-dimethoxy-5,6,5',6'-dimethylenedioxy-biphenyl-2-methylcarboxylate-2'-ethylcarboxylate). For regio-nonselective procedure, increasing the content of vinyl group on CTMB would lead to higher immobilization efficiency and enantio-selectivity.

[Cross-linked beta-cyclodextrin polymer used for bilirubin removal].

A new material for adsorption of bilirubin was synthesized with cross-linking reaction of beta-cyclodextrin. The kinetic adsorption behaviors of bilirubin such as the effects of temperature, pH, the initial bilirubin concentration as well as bovine seum albumin on the removal of bilirubin have been investigated. It is demonstrated that bilirubin could be adsorbed well on the prepared sorbent quickly and higher temperature favored the adsorpion of bilirubin.

Strategy for analysis and screening of bioactive compounds in traditional Chinese medicines.

Traditional Chinese medicines (TCMs), due to their long time clinic test and reliable therapeutic efficacy, are attracting increased global attention served as excellent pools of bioactive compounds for the discovery of new drugs. However, hundreds or even thousands of components are usually contained in traditional Chinese medicines and only a few compounds are responsible for the pharmaceutical and/or toxic effects. The large numbers of other components in traditional Chinese medicines make the screening and analysis of the bioactive components extremely difficult.

Enantiomer separation of dimethyl dicarboxy alpha-biphenyl (DDB) and its analogues on a covalently bonded cellulose tris-(3,5-dimethylphenylcarbamate) CSP.

Dimethyl dicarboxy alpha-biphenyl (DDB) and its analogues represent atropisomers which have been resolved on the covalently bonded cellulose tris-(3,5-dimethylphenylcarbamate) (CDMPC) CSP. Different kinds of alcohols, tetrahydrofuran (THF), and chloroform were employed as mobile phase modifiers (MPMs), and their influence on the retention and separation of the enantiomers was investigated. Ternary mobile phases (hexane/2-propanol/THF, hexane/2-propanol/chloroform) were employed to investigate the separation of the five enantiomers.

Preparation of a positively charged cellulose derivative chiral stationary phase with copolymerization reaction for capillary electrochromatographic separation of enantiomers.

A positively charged chiral stationary phase (CSP) was prepared by chemically immobilizing cellulose 3,5-dimethylphenylcarbamate onto methacryloyldiethylenetriaminopropylated silica (MCDEAPS) via a radical copolymerization reaction. The prepared CSP was evaluated for enantiomer separation in nonaqueous capillary electrochromatography (CEC). Electroosmotic flow (EOF) generated on the prepared CSP could be significantly improved with introduction of positive charges into the CSP, and separation of enantiomers in CEC has been achieved with mobile phases of ethanol and hexane-ethanol, respectively.

Separation and identification of compounds in Rhizoma chuanxiong by comprehensive two-dimensional liquid chromatography coupled to mass spectrometry.

A comprehensive two-dimensional liquid chromatographic separation system based on the combination of a CN column and an ODS column is developed for the separation of components in a traditional Chinese medicine (TCM) Rhizoma chuanxiong. Two columns are coupled by a two-position, eight-port valve equipped with two storage loops and controlled by a computer. The effluent is detected by both the diode array detector and atmospheric pressure chemical ionization (APCI) mass spectrometer.

Molecular imprinting of nitrophenol and hydroxybenzoic acid isomers: effect of molecular structure and acidity on imprinting.

Three nitrophenol isomer-imprinted polymers were prepared under the same conditions using 4-vinylpyridine as a functional monomer. Different recognition capacities for template molecules were observed for the three polymers. Another imprinting system with stronger acidity than nitrophenol isomers, 2-hydroxybenzoic acid (salicylic acid) and 4-hydroxybenzoic acid, was imprinted using 4-vinylpyridine or acrylamide as functional monomer respectively.

Synthesis of covalently bonded cellulose derivative chiral stationary phases with a bifunctional reagent of 3-(triethoxysilyl)propyl isocyanate.

A bifunctional reagent of 3-(triethoxysilyl)propyl isocyanate (TEPI) was initially adopted as a spacer reagent to prepare the bonded types of chiral stationary phases (CSPs) with cellulose derivatives. The silica-based CSPs were chemically prepared with non-regioselective and regioselective approaches and their chiral resolving capabilities were evaluated in terms of HPLC resolution of test enantiomers. It was observed that the chiral recognition capabilities of the non-regioselectively prepared CSPs were influenced by the amount of TEPI used.

[Comparison of endoscopic irsection and vaporization for superficial bladder cancer].

Objective: To evaluate the method and clinical value of endoscopic surgery by comparing endoscopic resection and vaporization for superficial bladder tumor.

Methods: 396 patients with superficial bladder papillary transitional cell carcinoma were treated by endoscopic therapy. 180 patients (Group A) were treated by transurethral resection of bladder tumor (TURBT) and 216 (Group B) by transurethral vaporization of bladder tumor (TVBT).

Unilamellar liposomes covalently coupled on silica gel for liquid chromatography.

Silica gel was used as a support for the covalent coupling of liposomes, which could overcome drawbacks of soft gel beads in column efficiency and separation speed. The influences of the concentration of added dimethylaminopyridine and reaction time on the chloroformate activation reaction of silica gel were investigated. Temperature and pH for covalent coupling of liposomes on the activated silica gel were also optimized.

Molecularly imprinted monolithic stationary phases for liquid chromatographic separation of enantiomers and diastereomers.

The method for preparation of molecularly imprinted monolithic stationary phase has been improved to achieve liquid chromatographic separation of enantiomers and diastereomers. By adopting low polar porogenic solvents of toluene and dodecanol and optimal polymerization conditions, the molecularly imprinted monolithic stationary phases with good flow-through properties and high resolution were prepared. Enantiomers of amino acid derivatives and diastereomers of cinchona alkaloids were completely resolved using the monolithic stationary phases.

[Simultaneous determination of trace Ni2+, Mn2+, Zn2+ and Cu2+ with microwave derivatization/ion-pair high performance liquid chromatography/meso-tetra(4-sulfophenyl)-porphyrin spectroscopy].

The best conditions for the reaction of meso-tetra(4-sulfophenyl)-porphyrin (TPPS4) with Mn2+, Ni2+, Zn2+ and Cu2+ have been investigated. A method for the fast determination of Ni2+, Mn2+, Zn2+ and Cu2+ has been developed: microwave derivatization at 750 W for 3 min, C18 column, acetonitrile-water(22.5:77.