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Chinese Journal of Chromatography
2005, Vol. 23, No. 3
Online: 30 May 2005

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研究报告

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Separation and Purification of Proteins on Monolithic Anion-Exchange Columns ZHANG Yihua, YANG Gengliang, ZHANG Xiaole, ZHAO Jumin, CAI Liping, CHEN Yi 2005, 23 (3):  219-222.  Abstract ( 2212 )   [Full Text(HTML)] () PDF (181KB) ( 746 )   A monolithic anion-exchange column with glycidyl methacrylate as the functional monomer and ethylene dimethacrylate as the cross linker was prepared by a free radical polymerization. The epoxide groups of the column were modified respectively by triethylamine, diethylamine and ethylenediamine that afforded anionic functionalities required for the anion-exchange chromatographic mode. The properties of the monolithic columns were investigated and the columns were successfully used as stationary phases of high performance liquid chromatography for the separation of proteins. For chromatographic analysis the effects of mobile phase composition and pH on the separation were investigated. The optimum separation for bovine serum albumin, lysozyme and glutathione was achieved with a gradient elution of mobile phase A ( 0.01 mol/L Tris-HCl (pH 　7.0)) and mobile phase B (mobile phase A+1.0 mol/L NaCl) with a flow rate of 1.0 mL/min at 25 ℃. The optimum purification for cellulase enzyme was obtained with a gradient elution of mobile phase A (0.01 mol/L Tris-HCl (pH　7.1)) and mobile phase B (mobile phase A+1.0 mol/L KBr) with the same flow rate and temperature. The columns exhibited good stability, and cellulase enzyme could be separated and purified quickly on the monolithic anion-exchange column modified by diethylamine.

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Study on Relationship Between Three-Dimensional Quantitative Structure and Retention ZHANG Yanling, GUO Yiran, WANG Yun, QIAO Yanjiang 2005, 23 (3):  223-228.  Abstract ( 2021 )   [Full Text(HTML)] () PDF (281KB) ( 528 )   A novel method to predict retention parameters of liquid chromatography is developed. By determining their lowest energy conformation, molecules are aligned according to one specific rule and the scope of the molecular field is defined around the aligned molecules. A positively charged sp3 carbon probe atom is used to calculate the characters of the molecular field such as the electrostatic and steric interaction energies. Then partial least square (PLS) method is exploited to analyze relationships between the a, c parameters of compounds and characters of the molecular field and finally comparative molecular field analysis (CoMFA) models are built, which are exploited to study three-dimensional quantitative structure-retention relationship (QSRR) between the a, c parameters of compounds in methanol/water on a reversed-phase C18 column and the characters of the molecular field. The models are applied to four different forms of arenes: alkylation-substituted benzenes, multi-ring arenes, chlorobenzenes and dinitro-substituted arenes. The results of PLS analyses show that three-dimensional models are obtained from the first three forms. The cross-validated q2 of the first three models are all above 0.5 and the non-cross-validated r2 of the first two forms are even above 0.995, so the predictive abilities of these models are considerable. The model of dinitro-substituted arenes is not so reasonable. The possible reason is that the nitro-substitutions are on different benzene rings. The novel method explored can be utilized to predict the retention parameters of the compounds, which are unknown but have the same kind of structure with the known compounds, and also provide information about the class of the compounds. The results of this project can be applied to direct the further study of the relationship between three-dimensional quantitative structure and retention parameters of liquid chromatography.

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Simultaneous Determination of 25 Persistent Organic Pollutants in Rice by Gas Chromatography-Mass Spectrometry with Selected Ion Monitoring Mode HOU Shengjun, CHEN Dandan, LI Xiang, LI Gang, YANG Qiang, MIN Shungeng, ZHONG Weike, CHU Xiaogang, WANG Daning 2005, 23 (3):  229-233.  Abstract ( 1998 )   [Full Text(HTML)] () PDF (237KB) ( 680 )   A multi-residue analytical method for the simultaneous determination of persistent organic pollutants (POPs) in rice samples was developed. POPs were extracted from rice with ethyl acetate/n-hexane(80∶20,v/v) by sonication, and determined by gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode. A fused silica capillary column DB-35MS (30 m× 0.25 mm i.d. ×0.25 μm) was employed. Operating conditions were as follows: injector port temperature, 300 °C; column temperature, programming; carrier gas, helium; flow rate, 1.0 mL/min; sample size, 1 μL with splitless injection. The mass spectrometric detector (MSD) was operated in electron impact ionization mode with an ionizing energy of 70 eV. Analysis was performed with selected ion monitoring (SIM) using one target and one or two qualifier ion.POPs were confirmed by their retention times, their qualifier and target ions, and their qualifier/target abundance ratios. Recovery studies were performed at 0.05, 0.1, and 0.5 mg/L spiked levels of each POPs, and the recoveries obtained ranged from 81.99% to 100.60% with relative standard deviations between 2.37% and 18.48%. The detection limits of the method ranged from 0.1 to 5 ng/g for the different POPs except endrin, trans-chlordane and cis-chlordane. The results show that the method developed is sensitive and reliable.

Reviews

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Development of Lewis Base-Modified Zirconia as Stationary Phases for High Performance Liquid Chromatography HU Yuling, FENG Yuqi, DA Shilu 2005, 23 (3):  234-237.  Abstract ( 2127 )   [Full Text(HTML)] () PDF (159KB) ( 574 )   The developments of the Lewis base-modified zirconia and mixed-oxide containing zirconia as stationary phases for high performance liquid chromatography (HPLC) are reviewed. Zirconia supports for HPLC based on modification with fluoride, phosphate, phosphonate, carboxylic acid, phenols, and protein, as well as cyclodextrin derivative, are covered. The application of modified-zirconia in capillary electrochromatography (CEC) is also discussed. Fifty-one references are cited.

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The Method Development of Subcritical Water Chromatography SU Yisong, JEN Jen-Fon, ZHANG Weibing, 2005, 23 (3):  238-242.  Abstract ( 2098 )   [Full Text(HTML)] () PDF (170KB) ( 637 )   Subcritical water is formed from pure water under high temperature and high pressure. The change of hydrogen-bond network results in the obvious change of physical properties of water such as polarity and viscosity. Subcritical water chromatography (SubWC), as a method of high performance liquid chromatography which takes subcritical water as mobile phase, is one kind of novel separation technique developed recently. Common gas chromatographic or liquid chromatographic instrument modified properly can be used as the instrument for SubWC. Both packed columns used in liquid chromatography and capillary columns used in gas chromatography can be applied in SubWC. The selectivity can be adjusted by changing column temperature or pressure and addition of the organic modifiers or salts in mobile phase. Both flame ionization detector and ultraviolet detector can be used as the detecting part of SubWC. Thus the range of its application and selection of optimal conditions are largely broadened. Currently this novel separation mode is still in the stage of research and development and mostly used in the fast separation of samples with polar and medium polar. The characteristics of SubWC are illustrated from the aspects and design of instruments, the elution characteristics of mobile phase and the selection of stationary phase. Moreover, the recent development of SubWC is systematically reviewed.

研究简报

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Preparation and Evaluation of Monolithic Silica Columns for Capillary Electrochromatography SHAO Hua, DENG Qiliang, LUN Zhihong, YAN Chao, GAO Ruyu 2005, 23 (3):  243-246.  Abstract ( 2288 )   [Full Text(HTML)] () PDF (210KB) ( 754 )   A solution of methacryloxypropyltrimethoxysilane in the presence of an acid catalyst, water, toluene and azobisisobutyronitrile (AIBN) was initiated at 60 ℃ for 24 h in a 100 μm i.d. capillary to prepare a porous monolithic silica column by a one-step, in situ, process. Various parameters, such as the volume of applied voltage, buffer pH, acetonitrile concentration and column temperature, were varied to assess their influence on retention mechanism, electroosmotic flow (EOF) and column efficiencies. The heat initiated sol-gel capillary monolithic column showed reversed-phase behavior. Furthermore, the homogeneous reactor was obtained using surfactant (sodium dodecyl sulfate, SDS). The baseline separation of 9 neutral compounds (thiourea, benzene, toluene, ethyl benzene, n-propylbenzene, naphthalene, n-butylbenzene, fluorene and anthracene) and 7 acidic, basic and neutral compounds (thiourea, o-aminophenol, phenol, benzene, o-methylaniline, α-naphthylamine, 2,4-dichloroaniline) can be obtained under optimized capillary electrochromatographic conditions. Column efficiency of 110000 plates/m was achieved for thiourea.

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Preparation of Vancomycin Chiral Stationary Phase and Study of Racemate Separation MENG Xiaorong, SHI Ling, ZHOU Huafeng, HOU Jingguo 2005, 23 (3):  247-250.  Abstract ( 2044 )   [Full Text(HTML)] () PDF (186KB) ( 571 )   By adopting the bifunctional group reagent methylene-di-paraphenylene iso-cyanate　(MDI), a ring antibiotic chiral stationary phase (CSP) was prepared in non-aqueous dimethylfomamide (DMF) with vancomycin which is a macrocyclic glycopeptide antibiotics bonded on γ-amidopropyl silica gel. It was used in the chiral separation in high performance liquid chromatography. The results showed that vancomycin CSP synthesized in this way can be well used in enantiomer separation of the chiral compounds in normal and reversed-phase. It can be confirmed that the separation capability in reversed-phase is better than that in normal phase. Seventeen pairs of enantiomers were separated in reversed-phase mode, and the results showed a wide range of application. The phosphorus buffer system was better than the triethylamine-acetic acid buffer system. The resolution of some chiral drugs such as D,L-dansyl amino acid has certain rule, and provides information about absolute configuration. The aging or denaturalization can not happen in the CSP when phase system was transformed, so it has some stability. The mechanism of the separation was analyzed and found to be the same as that of Armstrong.

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Preparation and Optimization of Polymer-Based Monolithic Stationary Phase for High Performance Liquid Chromatography WEI Yuanlong, ZOU Juanjuan, YANG Changlong, ZHANG Qinghe, ZHANG Weibing, WANG Fengyun, LI Tong 2005, 23 (3):  251-254.  Abstract ( 2379 )   [Full Text(HTML)] () PDF (211KB) ( 607 )   Unstirred in-situ polymerization was employed to directly produce glycidyl methacrylate-ethylene dimethacrylate copolymer (poly(GMA-co-EDMA) ) monoliths. Mercury intrusion method was adopted to measure some parameters of the monoliths, such as pore size distribution, porosity and specific surface area. Effects of key variables such as composition of pore-forming solvent mixture, temperature and content of cross-linking reagent, divinyl monomer on porous structure of monoliths were studied. The optimization of preparation conditions was achieved. Homogeneous micro porous structure was observed in the monoliths by scanning electron microscope. The effect of flow rate on back pressure was investigated, and good permeability of the monolithic stationary phase was obtained. The monolithic column was also used for the separation of goat serum and five oligonucleotides, and the results proved that the monolithic column is suitable for the separation of biopolymers.

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Study of Adsorption for Hemoglobin by Immobilized Copper Ion Affinity Membrane Chromatographic Column QIN Xiaorong, WU Lin, YI Delian, HU Lei, CAO Shuchao 2005, 23 (3):  255-257.  Abstract ( 3873 )   [Full Text(HTML)] () PDF (148KB) ( 636 )   Immobilized copper ion affinity membrane was prepared by using cellulose filter paper as matrix. The membrane was loaded into a chromatographic column designed in the laboratory and the immobilized copper ion affinity membrane chromatographic column was prepared. Hemoglobin (Hb) was adsorbed by the column and its adsorption rate was above 90%. The experimental process was as follows: a set of 5 immobilized copper ion affinity membranes were loaded into a column, uncombined copper ion was removed with 5 mL of sodium phosphate-citric acid buffer (pH 7); the Hb sample volume was 2 mL, and uncombined Hb was eluted with 10 mL of the buffer. The Hb concentration was determined by ultraviolet spectrophotometry at 405 nm. The major influence factors on hemoglobin adsorption rate such as Hb sample amount (1.58-31.6 mg/g (2 mL of sample volume)), pH value range (3.6-10.6), temperature range (25-50 ℃), and sample flow-rate (0.5-2.5 mL/min) were investigated. The optimal operation conditions were found as follows: the Hb sample amount of 3.16-7.90 mg/g, sample flow-rate of 0.5-1.0 mL/min, test temperature of room temperature, pH value range of 6-8. Compared with aqueous two-phase system, liquid-solid extraction system and the conventional column method, the membrane medium is cheaper and easier to be scaled up.

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Microchip Capillary Electrophoresis-Electrochemical Detection of Nitrite Using A Modified Carbon WEI Peihai, LI Guanbin, CHEN Liren 2005, 23 (3):  258-260.  Abstract ( 2018 )   [Full Text(HTML)] () PDF (155KB) ( 655 )   Carbon paste electrode modified with 3-mercaptopropyltrimethoxysilane copper (MPTMS-Cu) encapsulated in molecular sieve MCM-41 was prepared. The electrocatalytic behavior of the modified electrode towards the reduction of nitrite was studied in detail, including pH-dependence and composition-dependence studies. A microchip capillary electrophoresis-electrochemical detection system with the modified carbon paste as electrode was fabricated. The application of the system for the detection of nitrite is discussed. The detection was finished within 40 s under the following conditions: 50 mmol/L sodium acetate buffer at pH 5.8, -1.6 kV running voltage. The peak current was linear with the concentration of nitrite over 10.0 μmol/L-5.0 mmol/L and the detection limit was 4.0 μmol/L in pure water.

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Simultaneous Determination of Cimaterol, Clenbuterol and Salbutamol in Feeds by Capillary Zone DUAN Jianping, CHEN Hongqing, CHEN Ying, HUANG Ying, CHEN Guonan 2005, 23 (3):  261-263.  Abstract ( 2237 )   [Full Text(HTML)] () PDF (139KB) ( 656 )   A method for simultaneous determination of cimaterol, clenbuterol and salbutamol in feeds was developed by capillary zone electrophoresis. The effects of the experimental conditions on the separation and determination of cimaterol, clenbuterol and salbutamol have been examined. Under the optimum conditions, all three compounds were completely separated in 8 min. The linear range of cimaterol, clenbuterol and salbutamol was 0.1-1.0 mg/L, and the detection limits (S/N=3) were 0.02, 0.03 and 0.02 mg/L, respectively. The developed method has been used for the determination of spiked feed samples. The recoveries of cimaterol, clenbuterol and salbutamol were 89%-103%, 86%-91% and 83%-87%, respectively. The relative standard deviations for cimaterol, clenbuterol and salbutamol were 3.8%-4.3%, 3.6%-5.0% and 4.0%-5.6%, respectively. The proposed method is a sensitive, fast and simple method for the determination of cimaterol, clenbuterol and salbutamol in feeds.

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Determination of Chlorhexidine Acetate in Disinfectors by Capillary Electrophoresis ZOU Xiaoli, LI Yuanqian, MAO Hongxia, ZENG Hongyan 2005, 23 (3):  264-266.  Abstract ( 2251 )   [Full Text(HTML)] () PDF (134KB) ( 682 )   A method for the determination of chlorhexidine acetate in disinfectors using capillary electrophoresis (CE) was developed using the following conditions: detection wavelength, 254 nm; applied voltage, 15 kV; uncoated fused silica capillary column, 50 cm×75 μm i.d.; buffer, 15 mmol/L phosphate and acetonitrile (60∶40, v/v). Under the optimum conditions, chlorhexidine acetate in disinfectors was determinated in 4 min. The effects of different parameters, such as buffer component, buffer concentration, buffer pH value and electrophoretic voltage, on the CE analysis of chlorhexidine acetate were studied in detail. The linear range of the proposed method was 0.01-0.10 g/L. The detection limit was 0.004 mg/L. The relative standard deviation (RSD) of absorbance was 3.97% and the RSD of migration time was 2.99%. The spiked recoveries of samples were 91.4%-116.6%. The method was compared with the high performance liquid chromatographic method and the relative error was less than 4.0%. The proposed method was simple, quick and suitable for disinfector analysis.

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Purification and Characteristic of Proteinase Inhibitor GLPIA2 from Ganoderma lucidum by Submerged TIAN Yaping, ZHANG Kechang 2005, 23 (3):  267-269.  Abstract ( 2123 )   [Full Text(HTML)] () PDF (158KB) ( 648 )   A proteinase inhibitor GLPIA2 was purified to homogeneity from Ganoderma lucidum by submerged fermentation. The purification was carried out by ethanol fractional precipitation (30%-80%), gel-filtration on Superdex 200 column (30 cm×1.1 cm i.d.) and anion exchange on Source 30Q column (10 cm×1.6 cm i.d.). The gel chromatographic conditions were as follows: 50 mmol/L sodium phosphate as mobile phase with a flow rate of 1 mL/min with the effluent collection of 1 mL/tube and detection at 280 nm. The anion exchange chromatographic conditions were as follows: 50 mmol/L Tris-HCl (pH 8.8) containing different amounts of NaCl as mobile phase with a flow rate of 2 mL/min with the effluent collection of 5 mL/tube and detection at both 215 nm and 280 nm. Two active fractions named GLPIA1 and GLPIA2 corresponding to proteinase A inhibitory activities were pooled and lyophilized. GLPIA2 only has the absorption at 215 nm. The relative molecular mass of the inhibitor was 15000 as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The amino acid composition of GLPIA2 was analyzed by high performance liquid chromatography. The chromatographic conditions were as follows: C18 column (125 mm×4.0 mm i.d. ) with column temperature of 40 ℃; a mixture of 20 mmol/L sodium acetate-methanol-acetonitrile as mobile phase with a flow rate of 1 mL/min and detection at 338 nm. The results indicate that GLPIA2 is rich in acidic amino acid (Glu) and low in aromatic amino acids (Phe and Tyr). The interaction of some proteinases with GLPIA2 was investigated. The inhibitors are more potent against pepsin and yeast proteinase A than other proteinases.

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Determination of Ginsenoside Compound-K by Reversed-Phase High Performance Liquid Chromatography ZHOU Wei, LUO Zhenshi, ZHOU Pei 2005, 23 (3):  270-272.  Abstract ( 2316 )   [Full Text(HTML)] () PDF (154KB) ( 602 )   Ginsenoside compound-K content in ginseng is very low, while it is the main intestinal bacterial metabolite and the final absorption style of the major components, such as ginsenosides Rb1 and Rb2. The determination of ginsenoside compound-K in the fermentation liquor of ginseng saponins by reversed-phase high performance liquid chromatography was established. The separation was carried out under the following conditions: a Waters Symmetry C18 column (4.6 mm i.d.×150 mm, 5 μm) was used at 35 ℃ with acetonitrile-water (48∶52, v/v) as mobile phase at a flow rate of 1 mL/min. UV detection wavelength was set at 203 nm. The experimental results showed a good linear relationship between the peak area and mass concentration for ginsenoside compound-K within the range of 0.05-0.8 g/L (r=0.9998). The relative standard deviation of peak area (n=6) was 2.20%. The lowest detection limit (S/N=3) was 2.5 mg/L. The average recoveries (n=3) for the culture broth of ginseng saponins and notoginseng saponins were 98.6% and 99.7%, respectively. The method is rapid, simple, accurate and reproducible and can be utilized for the research and development of ginsenoside compound-K in pharmaceutical industry.

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High Performance Liquid Chromatographic Determination of Cinnamic Acid in Rabbit Plasma and WANG Rui, SUN Tianhui, JING Dan, CHEN Xiaohui, YU Zhiguo, BI Kaishun 2005, 23 (3):  273-275.  Abstract ( 2194 )   [Full Text(HTML)] () PDF (153KB) ( 587 )   A high performance liquid chromatographic method was developed to determine the content of cinnamic acid in rabbit plasma and the method was utilized for the study of pharmacokinetics. Cinnamic acid was separated by employing a column of Kromasil C18 (250 mm×4.6 mm i.d., 5 μm) and a mobile phase of methanol-acetonitrile-water-glacial acetic acid (10∶22∶55∶0.5, v/v) at a flow rate of 0.8 mL/min and room temperature with UV detection at 270 nm and phenylpropionic acid as internal standard. The extraction recoveries of the spiked samples at low, middle and high levels were 84.9%, 84.4%and 87.7%, respectively, while the method recoveries were 98.4% with relative standard deviation (RSD) of 5.5%, 99.2% with RSD of 3.6%, 100.1% with RSD of 3.7% in turn. The RSDs of intra-day and inter-day were both lower than 6%. Finally, the metabolism of cinnamic acid in rabbit plasma after medication of Guanxin Suhe Wan and Guanxin Suhe Capsule fitted in a first order absorption of two-compartment model. The method was found to be sensitive, accurate and precise, and is appropriate for the determination of cinnamic acid.

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Determination of Ligustrazine in Human Plasma by High Performance Liquid Chromatography with WENG Weiyu, SHEN Teng, XU Huinan, ZHANG Jianfang, HUANG Jianming, HUANG Zhaochang, CAI Jia 2005, 23 (3):  276-278.  Abstract ( 2078 )   [Full Text(HTML)] () PDF (151KB) ( 636 )   A high performance liquid chromatographic method was developed for the determination of ligustrazine in human plasma. The chromatographic separation was performed on a Luna C18 column (150 mm×4.6 mm i.d., 5 μm) at column temperature of 40 ℃. The mobile phase, a mixture of methanol-acetonitrile-acetate buffer of pH 5.0 (50∶8∶42, v/v), was delivered at a flow rate of 1.0 mL/min. The detection wavelength was 280 nm. Plasma samples were prepared with a C8 solid-phase extraction column. Linearity was confirmed in the mass concentration range of 25-5000 μg/L with the correlation coefficient of 0.9999. The extraction recovery of ligustrazine ranged from 96.72％ to 100.90％. The relative standard deviations (RSDs) of intra- and inter-day assay at the mass concentrations of 50, 500 and 3000 μg/L were less than 8.64% and the accuracies were between 99.59%-103.26%. The limit of detection (LOD) was 10 μg/L. The results of this method validation satisfactorily meet the acceptance criteria of bioanalysis and the method is applicable to the pharmacokinetic studies of ligustrazine in human beings.

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Separation of 3-Substituted-(R,S)-β-Alanine　Derivatives by High Performance Liquid Chromatography CHEN Yanqiang, QIU Xiaoping, XU Xiurong 2005, 23 (3):  279-281.  Abstract ( 1878 )   [Full Text(HTML)] () PDF (164KB) ( 654 )   3-Substituted-(R,S)-β-alanines derivatized by 1-fluoro-2,4-dinitro-5-L-valinamide (Marfey’s reagent) were successfully separated by reversed-phase high performance liquid chromatography. The separations were performed with gradient elution. The mobile phase A was acetonitrile containing 0.1%(v/v) trifluoroacetic acid and the mobile phase B was 0.1%(v/v) trifluoroacetic acid aqueous solution. Thirty-two pairs of 3-substituted-(R,S)-β-alanine derivatives, phenyl, substituted phenyl, naphthyl, substituted pyridyl and thienyl, were separated. The mobile phase A content was changed from 35% to 75% in 20 min. All (R-L)-diastereomers were eluted prior to the (S-L) ones. Substituents with larger hydrophobic parameters (π) gave longer retention times (tR) for their derivatives than those with smaller ones except for 3-hydroxyphenyl and 4-hydroxyphenyl substituents. The positioning of the substituents on benzene ring of β-alanines (β-Ala) also influenced tR and separation. 4-Subsituted-phenyl-(R,S)-β-Ala derivatives gave longer tR and better separation than 2-substituted isomers. The enantiomer excess values of R- and S-β-Ala were also determined.

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Determination of Quercetin in Apples by Reversed-Phase High Performance Liquid Chromatography MAO Li, JIN Nianzu, CHEN Jingheng 2005, 23 (3):  282-284.  Abstract ( 2100 )   [Full Text(HTML)] () PDF (151KB) ( 646 )   A method for the determination of quercetin in pulp and peel of apples by reversed-phase high performance liquid chromatography with internal standard was developed. Samples were frozen at -80 ℃ for 24 h, then added 6 mol/L hydrochloride under the protection of antioxidant 2,6-di-tert-butyl-p-cresol. The slurry was hydrolyzed thermostatically at 90 ℃ for 2 h and centrifugated for 10 min. The separation was performed on an ODS column (150 mm×6.0 mm i.d., 5 μm). Methanol-water (55∶45, v/v) (pH adjusted to 3.3 with acetic acid) was used as the mobile phase with a flow rate of 1.0 mL/min. The injection volume was 20 μL. The detection wavelength was 370 nm. The results showed that the quercetin content in pulp and in peel were 3.11-10.78 μg/g and 253.57-744.59 μg/g, respectively. The mean recovery of quercetin in apple pulp was 100.4%. The method is simple, accurate, and reliable.

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Simultaneous Determination of Four Fluoroquinolone Residues in Edible Chicken Tissues by DONG Linlin, LIU Yanhua, WANG Xia, ZHONG Feng,　PENG Li, YUE Xiuying,　GAO Lan 2005, 23 (3):  285-288.  Abstract ( 1899 )   [Full Text(HTML)] () PDF (186KB) ( 634 )   A reversed-phase high performance liquid chromatographic method with fluorescence detection was developed for the simultaneous analysis of ciprofloxacin, danofloxacin, enrofloxacin and sarafloxacin residues in edible chicken tissues. The analytes were extracted from chicken muscle, skin and fat, liver, kidney by aqueous potassium dihydrogenphosphate of different pH values through homogenization. The supernatant of the extract was applied onto a C18 solid phase extraction cartridge for clean-up. The separation was achieved on a C18 column, and the detection was performed with a fluorescence detector (excitation at 280 nm and emission at 450 nm). The four fluoroquinolones were analyzed in spiked samples of four chicken tissues with mean recoveries in the range of 53.9%-93.4% at spiked levels of 20-300 μg/kg. The relative standard deviations of inter-assay were no more than 23%. The detection limits of quantification were 20μg/kg for ciprofloxacin, enrofloxacin and sarafloxacin and 4μg/kg for danofloxacin. The method is simple, fast, and sufficient for routine analysis.

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Determination of Acrylamide in Heated Starchy Food by Liquid Chromatography-Electrospray Ionization ZHAO Rong, SHAO Bing, ZHAO Jie, WU Yongning, WU Guohua, XUE Ying 2005, 23 (3):  289-291.  Abstract ( 2290 )   [Full Text(HTML)] () PDF (158KB) ( 776 )   An isotope dilution liquid chromatographic-electrospray ionization tandem mass spectrometric method has been established for the determination of acrylamide in heated starchy food with a C18 analytical column and methanol-water containing 0.1% formic acid (2∶98, v/v) as mobile phases. The clean-up of samples was performed on an Oasis HLB solid phase extraction cartridge. The calibration curve of acrylamide showed good linearity in the range of 10-500 μg/L with correlation coefficient of 0.9995. The detection limit of the method was 6 μg/kg (S/N=3), and the limit of quantification was 20 μg/kg (S/N=10). The average recoveries at three levels ranged from 96.8% to 97.4% (n=5), and the relative standard derivations were lower than 10%.

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Study on Fingerprint Chromatograms of Water-Soluble Constituents of Salvia miltiorrhiza Bge. by ZHOU Xin, WANG Daoping, LIANG Guangyi, ZHANG Xueqin , ZHANG Zhonglin 2005, 23 (3):  292-295.  Abstract ( 1910 )   [Full Text(HTML)] () PDF (199KB) ( 633 )   The fingerprint chromatograms were established for the quality evaluation of Salvia miltiorrhiza Bge. by high performance liquid chromatography. The analysis was performed on a Zorbax SB-C18 column (5 μm, 4.6 mm i.d.×250 mm) with acetonitrile-water (containing 0.4% (v/v) acetic acid ) (the volume fraction of acetonitrile from 0 to 40% within 70 min) as mobile phase at a flow rate of 1.0 mL/min, and at a column temperature of 25 ℃.The detection wavelength was 254 nm. The relative standard deviations of relative retention values and relative peak areas were less than 3%. The mutual fingerprint of the extract of Salvia miltiorrhiza Bge. collected from Danshen Base in Tongren City of Guizhou Province was established by using the similarity calculation software of Chinese herbal fingerprint. The method is reliable and can be helpful in effectively controlling the quality of Salvia miltiorrhiza Bge.

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Simultaneous Determination of Josamycin, Theophylline and Paracetamol in Pharmaceutical Waste Water HUANG Xiaolan, XU Meiying 2005, 23 (3):  296-298.  Abstract ( 1986 )   [Full Text(HTML)] () PDF (144KB) ( 623 )   A high performance liquid chromatographic (HPLC) method was established for the simultaneous determination of three main pollutants (josamycin, theophylline and paracetamol) in pharmaceutical waste water. The three drug residues were concentrated with a SepPak C18 solid-phase extracted column, and eluted with methanol. The HPLC separation was performed on a Hypersil ODS column (200 mm ×4.6 mm i.d.) with a gradient eluting system of 0.025 mol/LKH2PO4-H3PO4 (pH 2.75)-methanol. The detection wavelengths were 230 nm for josamycin, 272 nm for theophylline, and 243 nm for paracetamol. The linear ranges of the drugs were 0.1-100 mg/L with correlation coefficients between 0.9993 and 0.9995. The recoveries were more than 93%, and relative standard deviations (n=6) were less than 2.1%. The detection limits (S/N=3) were less than 1.0 μg/L.

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Preparative Isolation and Purification of Calycosin and Formononetin from Astragalus membranaceus MA Xiaofeng, TU Pengfei,CHEN Yingjie , ZHANG Tianyou, WEI Yun 2005, 23 (3):  299-301.  Abstract ( 2250 )   [Full Text(HTML)] () PDF (177KB) ( 888 )   Preparative high-speed counter-current chromatography (HSCCC) was used for the separation of calycosin and formononetin from the ethyl acetate extract of Astragalus membranaceus Bge. var. mongholicus (Bge.) Hsiao. Calycosin was obtained by HSCCC with a binary phase solvent system composed of n-hexane-chloroform-methanol-water (1.5∶3∶3∶2, v/v). Then, formononetin was obtained with a system composed of n-hexane-chloroform-methanol-water (4∶4∶5∶4, v/v). The mobile phase was the lower phase and operated at a flow-rate of 2.0 mL/min, while the apparatus rotated at 800 r/min. High performance liquid chromatographic analysis of calycosin and formononetin revealed that their purities were over 95%. HSCCC is a useful method for the separation of natural products.

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Determination of Phytate and Phosphate in Plant Samples by Suppressed Conductivity Ion LIU Qiaoru, DONG Wenju, SHI Qizeng, YANG Guangrui 2005, 23 (3):  302-304.  Abstract ( 2123 )   [Full Text(HTML)] () PDF (158KB) ( 713 )   Determination of phytate and phosphate by suppressed conductivity ion chromatography was investigated. Plant samples were extracted with 1% (mass fraction) trichloroacetic acid （TCA）. After centrifugal settling, the supernatant was filtered with a 0.45 μm filter membrane before injected into the ion chromatographic system and detected by suppressed conductivity. The gradient eluent was composed of 0.22 mol/L sodium hydroxide solution, water and 50% (v/v) isopropyl alcohol solution. Phytate and phosphate were determined within 15 min, and no interference was found in the presence of fluorate, chlorate, nitrate, sulphate and TCA. Good linearities for phytate and phosphate were obtained in the ranges of 5-400 mg/L (r2=0.9994) and 5-500 mg/L (r2=0.9999), and the detection limits (S/N=3) were 3.5 mg/L and 1.5 mg/L, respectively. The average recoveries for phytate and phosphate were 99.8% and 98.4%, and their relative standard deviations were 1.98% and 2.09%, respectively.

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Preparation of Stationary Phases of Four β-Cyclodextrin Derivatives for Gas Chromatography by Sol-Gel Technique GE Xiaoxia, QI Meiling, LI Liang, HUA Fei, SHAO Qinglong, FU Ruonong 2005, 23 (3):  305-307.  Abstract ( 2068 )   [Full Text(HTML)] () PDF (158KB) ( 615 )   Heptakis(2,3,6-tri-O-ethyl)-β-cyclodextrin (CD) (perethylated-β-CD), heptakis(2,3,6-tri-O-propyl)-β-CD (perpropylated-β-CD), heptakis(2,3,6-tri-O-octyl)-β-CD (peroctylated-β-CD), and (2,6-di-O-benzyl)-β-CD were used as stationary phases to prepare columns for gas chromatography by sol-gel technique. The method of coating the columns is similar to the dynamic method and the time required was shortened. Chromatographic characteristics such as column efficiency (around 3000 plates/m), column stability and reproducibility (relative standard deviation below 8.5%) were studied. The columns exhibited good separation ability for disubstituted benzene isomers, especially for xylenes and cresols. In addition, the three peralkylated-β-CD columns offer better selectivity than the (2,6-di-O-benzyl)-β-CD column.

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Determination of Organochlorine Pesticide Residues in Nine Herbs by Solid-Phase Extraction and YAN Zheng, FENG Di, LI Shenjie, ZHAO Yakui, YANG Hui 2005, 23 (3):  308-311.  Abstract ( 2230 )   [Full Text(HTML)] () PDF (195KB) ( 640 )   The solid-phase extraction and capillary gas chromatography was introduced for determining 13 organochlorine pesticide residues including α-benzene hexachloride (BHC), β-BHC, γ -BHC, δ-BHC, p,p′-dichloro-diphenyl-dichloroethylene (pp′-DDE), p,p′-dichloro-diphenyl-dichloroethane (pp′-DDD), o,p′-dichloro-diphenyl-trichloroethane (op′-DDT), pp′-DDT, heptachlor (HEPT), aldrin, heptachlor epoxide (HCE), dieldrin and endrin in Scutellaria baicalensis, Salvia miltiorrhiza, Belamcanda chinensis, Paeoniae lactiflora, Angelica dahurica, Arisaema erubescens, Fructus arctii, Anemarrhena asphodeloides and Platycodon grandiflorum.The organochlorine pesticides were extracted from herbs with mixed solvents of acetone and n-hexane by ultrasonic and cleaned up by Florisil solid-phase extraction column. Then, the extract was separated by capillary column (30 m×0.25 mm i.d.×0.25 μm ) and detected by electrochemical detector. The carrier gas was N2(99.999%) with the flow rate of 1.4 mL/min. The split ratio was 1∶2.2. The injector temperature was 220 ℃ and the detector temperature was 330 ℃. The column temperature was increased by the rate of 20 ℃/min from 100 ℃ to 190 ℃ (hold for 1.0 min), then to 235 ℃ by the rate of 4 ℃/min and hold for 7 min at 235 ℃. The good linearities were obtained for 13 organochlorine pesticides. The detection limits were between 0.064-0.61 μg/L. The average recoveries were between 87.3%-102.3% and relative standard deviations of 1.3%-6.8%. The method is effective, fast and accurate.

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Determination of Acrylamide in Fried Starchy Foods by Gas Chromatography-Mass Spectrometry ZHONG Weike, CHEN Dongdong, YONG Wei, LIU Zhiming, QIU Yueming, TANG Yingzhang 2005, 23 (3):  312-314.  Abstract ( 2226 )   [Full Text(HTML)] () PDF (155KB) ( 756 )   A method was developed for the determination of acrylamide in fried starchy foods using isotope dilution gas chromatograpy-selected mass spectrometry (GC-MS). The acrylamide was extracted from samples by water, then centrifuged and cleaned up by a column of graphitized carbon black. Acrylamide was derivatized through bromination at low pH and low temperature and determined by GC-MS. With the aid of the 13C-substituted acrylamide internal standard, the mass spectrum in GC-MS was interpreted, and the content of acrylamide was measured. The limit of quantitative detection (S/N>10) was 5 μg/kg and the recovery was in the range of 90％-105％ and relative standard deviation is 6.3％. The levels of acrylamide in some fried foodstuffs such as French fries was surveyed using the method. French fries were found to contain 278-4518 μg/kg acrylamide. It means that the content of acrylamide in French fries is 10000 times higher than the drinking water guideline of World Health Organization for acrylamide.