List of Issues

Chinese Journal of Chromatography
2012, Vol. 30, No. 01
Online: 28 January 2012

Previous Issue    Next Issue



For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Highlight

Select

Mixed-mode chromatography of biopolymers-traditional concept of liquid chromatography being changed GENG Xindu 2012, 30 (01):  1-2.  DOI: 10.3724/SP.J.1123.2012.01005 Abstract ( 1624 )   [Full Text(HTML)] () PDF (63KB) ( 507 )

Reviews

Select

New technique for nanoparticle capillary electrophoresis/microfluidic chip and its uses in enantioselective separation CHEN Jie1, DING Guosheng2, YUE Chunyue1, TANG Anna1* 2012, 30 (01):  3-7.  DOI: 10.3724/SP.J.1123.2011.09037 Abstract ( 2458 )   [Full Text(HTML)] () PDF (139KB) ( 678 )   Nanoparticles have been widely used in separation science due to their large specific surface area and good biocompatibility. Nanoparticle capillary electrophoresis (CE)/microfluidic chip (MC) technique is the hybrid of nanomaterial and the CE/MC technique. By being adsorbed or bonded onto the inner surface of the capillary, the nanoparticles can interact with the analytes as stationary phase. As a kind of separation medium, the nanoparticles can also participate in the separation process acting as a pseudostationary phase (PSP) to improve the separation efficiency and selectivity. Chirality is one of the intrinsic characters of the nature. It is important to develop the novel, fast, highly efficient and sensitive chiral separation technique in many research areas, such as stereoselective synthesis of enantiomers, pharmacology, chiral compounds purity check and environment monitoring. Herein, the recent applications of different types of nanoparticles such as polymer nanoparticles, magnetic nanoparticles, gold nanoparticles and carbon nanotubes in enantioseparation by CE/MC are reviewed, and the future developments in this area are also prospected.

Articles

Select

Exploring the mechanism of Rhizoma coptidis in treating type IIdiabetes mellitus based on metabolomics by gas chromatography-mass spectrometry WANG Jing1,2, YUAN Zimin2, KONG Hongwei1*, LI Yong1, LU Xin1, XU Guowang1 2012, 30 (01):  8-13.  DOI: 10.3724/SP.J.1123.2011.08039 Abstract ( 2050 )   [Full Text(HTML)] () PDF (232KB) ( 666 )   Metabolomics was used to explore the mechanism of Rhizoma coptidis in treating type II diabetes mellitus. The rat model of type II diabetes mellitus was constructed by an injection of streptozocin (40 mg/kg), along with diets of fat emulsion. The rats were divided into four groups, the control group, the model group, the Rhizoma coptidis group (10 g/kg) and the metformin group (0.08 g/kg). After the treatment for 30 d, blood samples were collected to test biomedical indexes, and 24 h urine samples were collected for the metabolomics experiment. In the Rhizoma coptidis group, fasting blood glucose (FBG), total cholesterol (TC) and total plasma triglycerides (TG) were significantly decreased by 59.26%, 58.66% and 42.18%, respectively, compared with those in the model group. Based on gas chromatography-mass spectrometry, a urinary metabolomics method was used to study the mechanism of Rhizoma coptidis in treating diabetes mellitus. Based on the principal component analysis, it was found that the model group and control group were separated into two different clusters. The Rhizoma coptidis group was located between the model group and the control group, closer to the control group. Twelve significantly changed metabolites of diabetes mellitus were detected and identified, including 4-methyl phenol, benzoic acid, aminomalonic acid, and so on. After diabetic rats were administered with Rhizoma coptidis, 7 metabolites were significantly changed, and L-ascorbic acid and aminomalonic acid which related with the oxidative stress were significantly regulated to normal. The pharmacological results showed that Rhizoma coptidis could display anti-hyperglycemic and anti-hyperlipidemic effects. The Rhizoma coptidis had antioxidation function in preventing the occurrence of complications with diabetes mellitus to some extent. The work illustrates that the metabolomics method is a useful tool to study the treatment mechanism of traditional Chinese medicine.

Select

Determination of seven toxaphene congeners in Ginseng and Milkvetch Root by gas chromatography-tandem mass spectrometry TIAN Shaoqiong1,2, MAO Xiuhong2, MIAO Shui2, JIA Zhengwei2, WANG Ke2, JI Shen2* 2012, 30 (01):  14-20.  DOI: 10.3724/SP.J.1123.2011.09019 Abstract ( 1878 )   [Full Text(HTML)] () PDF (344KB) ( 377 )   A novel method for the determination of representative toxaphene congeners in traditional Chinese herbal medicines was developed. Ginseng and Milkvetch Root were selected as the samples and seven toxaphene congeners were selected as the monitoring objects. The samples were extracted by accelerated solvent extraction with cyclohexane-acetone (9:1, v/v), then cleaned-up by Florisil solid phase extraction with hexane as the eluent and the residues were detected by gas chromatography-electron ionization tandem mass spectrometry (GC-EI-MS/MS) in multiple reaction monitoring (MRM) mode. The performance was demonstrated by the analysis of Ginseng and Milkvetch Root samples spiked with toxaphene congeners at three concentration levels of 0.005, 0.01 and 0.1 mg/kg. The recoveries ranged from 72.4% to 105% with the relative standard deviations (RSDs) of 0.96%~10.4%. The limits of detection (LODs) were 0.2~1.7 μg/kg. This method is sensitive and efficient in the aspect of extraction, and can be applied to monitor the residue of toxaphene congeners in Ginseng and Milkvetch Root.

Select

Determination of 9 residual acrylic monomers in acrylic resins by gas chromatography-mass spectrometry coupled with microwave assisted extraction LAI Ying*, LIN Rui, CAI Luxin, GE Xiuxiu, HUANG Changchun 2012, 30 (01):  21-26.  DOI: 10.3724/SP.J.1123.2011.09011 Abstract ( 2480 )   [Full Text(HTML)] () PDF (207KB) ( 495 )   A reliable gas chromatography-mass spectrometry (GC-MS) method was developed for the determination of 9 residual acrylic monomers (methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl acrylate, butyl methacrylate, styrene, acrylic acid and methacrylic acid) in acrylic resins. Solid resin was precipitated with methanol after microwave assisted extraction with ethyl acetate for 30 min, and liquid resin was diluted with methanol directly. The nine acrylic monomers got a good separation within 20 min on a DB-WAX column. The limits of quantification (LOQs, S/N=10) of the method were in the range of 1~10 mg/kg for liquid resin and 3~50 mg/kg for solid resin. The calibration curves were linear within 1~500 mg/L range with correlation coefficients above 0.995. The recoveries ranged from 84.4%to 108.6% at five spiked levels. The sensitivity, recovery and selectivity of the method can fully meet the requirements of practical work.

Select

Determination of 23 phthalate esters in food by solid-phase extraction coupled with gas chromatography-mass spectrometry ZHENG Xianghua1, LIN Liyi1, FANG Enhua1, HUANG Yonghui2, ZHOU Shuang1, ZHOU Yu1, ZHENG Xiaoyan2, XU Dunming1* 2012, 30 (01):  27-32.  DOI: 10.3724/SP.J.1123.2011.08019 Abstract ( 2280 )   [Full Text(HTML)] () PDF (202KB) ( 834 )   A method for the simultaneous determination of 23 phthalate esters in food samples by solid-phase extraction coupled with gas chromatography-mass spectrometry (SPE-GC-MS) was developed and evaluated. The samples were extracted with hexane or acetonitrile, and cleaned up with a glass ProElut PSA SPE column. The identification and quantification were performed by GC-MS in selected ion monitoring (SIM) mode. The extraction processes of different foods were investigated. The calibration curves of phthalate esters showed good linearity in the range of 0.05~5 mg/L (0.5~5 mg/L for diisononyl phthalate (DINP), diisodecyl-phthalate (DIDP)) with the correlation coefficients (r) between 0.9848 and 0.9996. The limits of detection of phthalate esters in food samples ranged from 0.005 to 0.05 mg/kg (S/N=3) and the limits of quantification ranged from 0.02 to 0.2 mg/kg (S/N=10). The average recoveries of 23 analytes spiked in 10 kinds of food matrices ranged from 77% to 112% with the relative standard deviations (RSDs, n=6) of 4.1%~12.5%. The method is suitable for the determination of 23 phthalate esters simultaneously in foodstuffs with easy operation, high accuracy and precision.

Select

Determination of streptomycin and dihydrostreptomycin residues in tomato paste by tandem dual solid phase extraction column-liquid chromatography-tandem mass spectrometry GONG Zhiguo1, SU Min1, JI Xincheng1*, LI Shiyu1, WAN Yuping2 2012, 30 (01):  33-38.  DOI: 10.3724/SP.J.1123.2011.08009 Abstract ( 1849 )   [Full Text(HTML)] () PDF (197KB) ( 346 )   The method was specifically developed for the simultaneous determination of streptomycin and dihydrostreptomycin residues in tomato paste by tandem dual solid phase extraction (SPE) column cleanup-liquid chromatography-tandem mass spectrometry. The residues were extracted from the samples with phosphate buffer solution (pH 4). The cleanup was performed by the way of dispersive solid phase extraction and tandem dual solid phase extraction column. The polar chromatographic column was used to complete the separation of the analytes under gradient elution and the analytes were detected in multiple reaction monitoring (MRM) mode via positive electrospray ionization (ESI+). The external standard calibration curves were used for the quantification. The linear ranges were from 0.01 to 0.2 mg/L with a good linear relationship (r＞0.999) for streptomycin and dihydrostreptomycin. The limit of quantification (LOQs) was 0.02 mg/kg for the both analytes. The recovery range was from 71% to 101% with the relative standard deviations (RSDs) between 2.3% and 15%. It was indicated that this method is accurate, easier, more sensitive, and has a better purification effect in the monitoring and analysis. The method is accurate and specific to monitor and analyze of streptomycin and dihydrostreptomycin residues in tomato paste and its products.

Select

Determination of glyphosate and aminomethylphosphonic acid in rice using hydrophilic interaction chromatography-tandem mass spectrometry JIANG Yan, CAO Zhaoyun, JIA Ruilin, QI Hui, CHEN Mingxue* 2012, 30 (01):  39-44.  DOI: 10.3724/SP.J.1123.2011.08040 Abstract ( 2308 )   [Full Text(HTML)] () PDF (231KB) ( 412 )   AA method was developed for the simultaneous determination of glyphosate (Gly) and aminomethylphosphonic acid (AMPA) residues in rice using hydrophilic interaction chromatography-tandem mass spectrometry (HILIC-MS/MS). The samples were extracted with water, and purified using a C18 solid phase extraction cartridge followed by an ultrafiltration membrane to remove interfering materials. Gly and AMPA were separated on an HILIC column with the mobile phases of 1 mmol/L ammonium acetate (pH 11.0 adjusted with ammonium hydroxide) and acetonitrile, and finally detected with negative electrospray ionization (ESI~) in multiple reaction monitoring (MRM) mode. The matrix-matched external standard calibration curves were used for quantitative analysis. The sample pretreatment of Gly and its metabolite was successfully carried out without any derivatization. Under the optimal analytical conditions, the linearities of Gly and AMPA were in the concentration ranges of 0.001 to 0.250 mg/L and 0.0025 to 0.250 mg/L respectively, with the correlation coefficients of 0.9995 for the both analytes. The limits of detection (S/N=3) of the method were 0.010 mg/kg for Gly, and 0.020 mg/kg for AMPA. For all the samples, the mean spiked recoveries of Gly and AMPA were in the range from 96.3% to 107.3% at 3 spiked levels (0.100, 0.500 and 2.500 mg/kg), and the relative standard deviations (RSDs, n=3) were in the range of 1.3%~9.1%. The method is easy, fast, sensitive and accurate, and can meet the requirements of the determination of Gly and AMPA pesticide residues in rice.

Select

Determination of 3-methyl-quinoxaline-2-carboxylic acid in animal and aquatic products by ultra performance liquid chromatography-tandem mass spectrometry Lv Hailuan1, WU Congming1*, CHENG Linli1, ZHANG Suxia2, SHEN Jianzhong2 2012, 30 (01):  45-50.  DOI: 10.3724/SP.J.1123.2011.09010 Abstract ( 1714 )   [Full Text(HTML)] () PDF (218KB) ( 430 )   An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established for the determination of 3-methyl-quinoxaline-2-carboxylic acid (MQCA) in animal tissues and aquatic products. The analyte was extracted with 0.2 mol/L hydrochloric acid. The extract was cleaned up on a Bond Elut C18 cartridge. Then the eluate was collected and evaporated to dryness under nitrogen gas at 35 ℃. The residue was redissolved in acetonitrile containing 0.1% (v/v) formic acid. The identification was performed by multiple reaction monitoring in positive electrospray ionization. The quantification was done by external standard method. The calibration curves showed good linearity within the range of 2~500 μg/L with the correlation coefficients (r2) greater than 0.990. The limits of detection (LODs) of MQCA in pork, swine liver, pig kidney, fish, prawn, and crab were 0.90, 1.51, 0.94, 1.04, 1.62 and 1.80 μg/kg, respectively; and the limits of quantification (LOQs) were 3.00, 5.02, 3.13, 3.46, 5.40 and 6.00 μg/kg, correspondingly. The recoveries of MQCA in animal tissues and aquatic products were 73.6%~89.0% at the spiked levels of 3~100 μg/kg. The intra-day relative standard deviations (RSDs, n=5) were less than 15%, and inter-day RSDs (n=3) were less than 20%. The results demonstrated that the sensitivity, accuracy, and precision were fit for the requirements of veterinary drug residue analysis.

Select

Simultaneous determination of nine microcystins in surface water by solid phase extraction and ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry ZHANG Ming*, TANG Fangliang, CHEN Feng, XU Jianfen, ZHANG Lina 2012, 30 (01):  51-55.  DOI: 10.3724/SP.J.1123.2011.09003 Abstract ( 1732 )   [Full Text(HTML)] () PDF (209KB) ( 379 )   A method has been developed for the simultaneous determination of nine microcystins (MCs) in surface water by solid phase extraction-ultra performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (SPE-UPLC-ESI-MS/MS). The samples were enriched and purified by an HLB solid phase extraction column. The separation was performed on an ACQUITY UPLCTM system with a BEH C18 column with the gradient elution of acidified acetonitrile and water (both containing 0.1%(v/v) formic acid). The nine MCs were determined in the modes of electrospray positive ionization (ESI+) and multiple reaction monitoring (MRM). Good linearities were observed in the ranges of 0.1~50 μg/L for MC-RR and 0.5~100 μg/L for the others with correlation coefficients over 0.9990 and the limits of detection for the nine MCs were in the range of 0.1~0.5 ng/L. The recoveries were in the range of 75.8%~109% in the three spiked levels of 1.0, 10 and 50 μg/L with the relative standard deviations of 0.49%~10.0%. The method is characterized by high sensitivity and precision, extensive analytical range and quick analytical rate. This method was used in the analysis of water samples from two reservoirs situated in Hangzhou, and the 3 and 8 microcystins were detected individually.

Select

Molecularly-imprinted solid phase extraction coupled with high performance liquid chromatography for the determination of ractopamine in feed samples HUANG Yi, ZHANG Qingjie, LIU Min, WANG Xufeng, LI Jianqin, HE Limin* 2012, 30 (01):  56-61.  DOI: 10.3724/SP.J.1123.2011.08033 Abstract ( 2179 )   [Full Text(HTML)] () PDF (262KB) ( 429 )   Molecularly imprinted polymers (MIPs) with high selectivity to ractopamine (RAC) were prepared by using RAC as template, acrylamide (AM) as monomer, and ethylene glycol dimethacrylate (EGDMA) as cross-linker. The effects of four porogens (methanol, acetonitrile, acetone, and chloroform-methanol) with triethylamine (30:1, v/v) on the recognition capability of MIPs to RAC and the morphological characteristics of the polymers were investigated. Orthogonal test was used to optimize the preparation of MIPs, and the optimal compositions were as follows: 1.0 mmol RAC, 4.0 mmol AM, 20.0 mmol EGDMA, 6.0 mL acetonitrile-triethylamine (30:1, v/v), and 50.0 mg azobisisobutyronitrile. A high performance liquid chromatographic method based on molecularly-imprinted solid-phase extraction (MISPE) was developed for the determination of ractopamine in feed samples. The limit of detection (LOD, S/N=3) of ractopamine was 0.1 mg/kg. The linear range was 0.50~100 mg/L (r=0.9994). Mean recoveries of RAC spiked in 3 kinds of feed samples at 1.0, 10 and 100 mg/kg were above 80% with the relative standard deviations of less than 10%. The clean-up efficiency of MISPE was ideal for feed samples. The method is more sensitive and reproduciable than the standard analytical method for the determination of RAC in feed matrices.

Select

Simultaneous determination of organic acids and saccharides in lactic acid fermentation broth from biomass using high performance liquid chromatography MA Rui, OUYANG Jia*, LI Xin, LIAN Zhina, CAI Cong 2012, 30 (01):  62-66.  DOI: 10.3724/SP.J.1123.2011.09033 Abstract ( 2882 )   [Full Text(HTML)] () PDF (176KB) ( 746 )   A high performance liquid chromatographic method for the simultaneous determination of organic acids and saccharides in lactic acid fermentation broth from biomass was developed. A Bio-Rad Aminex HPX-87H column was used at 55 ℃. The mobile phase was 5 mmol/L sulfuric acid solution at a flow rate of 0.6 mL/min. The samples were detected by a refractive index detector (RID). The results showed that six organic acids and three saccharides in fermentation broth were completely separated and determined in 17 min. The linear correlation coefficients were above 0.9998 in the range of 0.15~5.19 g/L. Under the optimized conditions, the recoveries of the organic acids and saccharides in Rhizopus oryzae fermentation broth at two spiked levels were in the range of 96.91%~103.11% with the relative standard deviations (RSDs, n=6) of 0.81%~4.61%. This method is fast and accurate for the quantitative analysis of the organic acids and saccharides in microbial fermentation broths.

Select

Preparation of immunoaffinity chromatographic column specific to diniconazole and its applications to the pretreatment of samples JIN Yahui, WANG Minghua* 2012, 30 (01):  67-70.  DOI: 10.3724/SP.J.1123.2011.09036 Abstract ( 1549 )   [Full Text(HTML)] () PDF (146KB) ( 325 )   The purified anti-diniconazole antibody was polymerised to hydrolytic tetramethoxysilane (TMOS) to synthesize the immunosorbent for the immunoaffinity chromatographic (IAC) column specific to diniconazole. The optimized conditions of the IAC were as follows: water as equilibrium and adsorbent medium, 30% and 50% (v/v) methanol aqueous solutions as eluents. The results showed that the dynamic column capacity was up to 125.4 μg/g of bed volume. The river water and fruit samples spiked with diniconazole were cleaned up and enriched by the IAC, and the diniconazole in eluant was determined by high performance liquid chromatography. The average recoveries (n=5) of diniconazole in river water sample were 90.36%~100.14% with relative standard deviations (RSDs) of 2.03%~6.08%, and the average recoveries in fruit samples were 85.55%~94.02% with RSDs of 3.38%~6.78%. The IAC clean-up procedure provided an effective pretreatment method for the determination of diniconazole in sample media such as river water and fruits.

Select

Simultaneous determination of bensulfuron-methyl and mefenacet residues in paddy field using high performance liquid chromatography YANG Lihua1,2, GONG Daoxin1,2*, TANG Jing1,2, LUO Junkai1,2, DING Chunxia1,3 2012, 30 (01):  71-75.  DOI: 10.3724/SP.J.1123.2011.09021 Abstract ( 1883 )   [Full Text(HTML)] () PDF (163KB) ( 322 )   An analytical method of high performance liquid chromatography (HPLC) was established for the simultaneous determination of bensulfuron-methyl and mefenacet residues in paddy field (paddy water, soil and rice plant). The residues in the paddy water was extracted with methylene chloride, and the soil with alkaline mixed solution of acetonitrile-methylene chloride (1:1, v/v). The rice plant was extracted with alkaline methylene chloride which was cleaned up by a Florisil column. The separation was performed on a stainless steel C18 column (150 mm×4.6 mm, 5 μm) at 30 ℃ by HPLC with an ultraviolet detector (UVD) at 238 nm, and water-methanol (30:70, v/v) as the mobile phase at a flow rate of 0.5 mL/min. The quantification was performed by external standard. The calibration curves were linear between the peak area and the concentration in the range of 0.05~5.00 mg/L for bensulfuron-methyl and mefenacet, and the correlation coefficients were more than 0.9999. The average recoveries of the two herbicides spiked in the paddy water, soil and rice plant at the three concentration levels of 0.05, 0.10 and 1.00 mg/kg ranged from 85.39% to 113.33% with the relative standard deviations of 0.91%~10.24%. The method is characterized by simplicity, sensitivity and accuracy.

Select

Determination of trace perchlorate in groundwater by solid phase extraction-ion chromatography YE Long, YOU Hong*, YAO Jie, SU Huailong 2012, 30 (01):  76-79.  DOI: 10.3724/SP.J.1123.2011.08054 Abstract ( 1581 )   [Full Text(HTML)] () PDF (145KB) ( 318 )   A comprehensive analytical method based on solid phase extraction-ion chromatography (SPE-IC) has been developed for the determination of trace perchlorate in groundwater. An amount of 0.7 liter of groundwater was enriched by a solid phase extraction column after pretreatment to remove the interference ions and then the column was eluted by 6 mL 1% NaOH solution. After filtration of the concentrated liquor with a filter membrane (0.45 μm), the liquor was analyzed on an ion chromatograph (IC) equipped with an Ion Pac AS20 separation column and a 50 μL injection loop, eluted with 40 mmol/L KOH solution. The method detection limit (MDL) and limit of determination (LOD) of perchlorate were 0.15 μg/L and 0.60 μg/L, respectively. The recovery was in the range of 99.7%~100.5% when the sampling concentrations were in the range of 1~15 μg/L. The method is economical and effective. It can be applied to determine trace perchlorate in groundwater. The perchlorate in groundwater samples got from the areas surrounding Harbin was determined by this method. The relative errors were in the range of 1.85%~9.24% between the results got by the SPE-IC and ion chromatography-tandem single quadrupole mass spectrometry.

Select

Preparation of immunoglobulin from chicken egg yolk by anion-exchange chromatography WANG Liying, MA Meihu*, CAI Zhaoxia, JIN Yongguo, HUANG Xi 2012, 30 (01):  80-85.  DOI: 10.3724/SP.J.1123.2011.09005 Abstract ( 1969 )   [Full Text(HTML)] () PDF (287KB) ( 421 )   An economical, effective and large-scale method for the preparation of immunoglobulin of chicken egg yolk (IgY) was developed. The method was based on an improved water dilution combining with polyethylene glycol 6000 (PEG6000) precipitation and anion-exchange chromatography. The egg yolk was diluted with 8 volumes of aseptic water, the pH of which was adjusted to 5.2 with 0.1 mol/L HCl, then the mixture was centrifuged at 5000×g after standing for 8 h at 4 ℃. The crude IgY was obtained from the supernatant layer with the yield of 93.47%. The purification of IgY was achieved by 6% PEG6000 precipitation and DEAE-Toyopearl 650 M anion-exchange chromatographic packing. The optimum purified conditions by ion-exchange chromatography were as follows: equilibration with 0.05 mol/L phosphate buffer (pH 7.0) and elution with 0.075 mol/L phosphate buffer (pH 7.0). The purity of the IgY fraction was consistently greater than 95% with high activity (73.77%) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). This method is superior to the traditional ion-exchange chromatography that can’t simultaneously obtain high purity and high recovery. Moreover, this method is suitable for a large-scale IgY preparation from chicken egg yolk.

Technical Notes

Select

Preparation and characterization of recombinant protein A affinity packing GUO Mingming1,2, WANG Junling2, WU Yanzhuo2, XU Mingbo2*, GAO Xiangdong1 2012, 30 (01):  86-90.  DOI: 10.3724/SP.J.1123.2011.08018 Abstract ( 1958 )   [Full Text(HTML)] () PDF (199KB) ( 377 )   To obtain an excellent antibody purification medium, affinity chromatographic packing with recombinant staphylococcal protein A (rProtein A) was synthesized and verified. With E. coli cells harboring the recombinant plasmid, the rProtein A was expressed and purified, then was conjugated to epichlorohydrin-activated Sepharose 4 Fast Flow to prepare an affinity chromatographic packing. The performances of the packing were validated with rabbit anti-urate oxidase. After the reaction, the concentration of rProtein A coupled to Sepharose 4 Fast Flow was 1.5×10~4 mol/L. Scatchard analysis of the binding isotherm for IgG showed excellent binding capacity on the adsorbent, giving a dissociation constant (Kd) of 2.28×10~7 mol/L and a theoretical maximum adsorption capacity of 20.697 g/L. The identification showed the packing was stable in 0.1 mol/L NaOH solution at 1 h. By using the packing, the pure antibody exhibited on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was obtained from rabbit serum after one-step elution, with 96.1% of yield and 19 mg IgG for one milliliter of gel. The research laid the foundation of the localization of rProtein A affinity packing.

Select

Determination of thiophanate-methyl and carbendazim in cucumber and soil by QuEChERS-high performance liquid chromatography-triple quadrupole tandem mass spectrometry ZHANG Zhiyong1, GONG Yong2, SHAN Weili2, JIAN Qiu2, SHEN Yan1, LIU Xianjin1* 2012, 30 (01):  91-94.  DOI: 10.3724/SP.J.1123.2011.07014 Abstract ( 2607 )   [Full Text(HTML)] () PDF (143KB) ( 536 )   A method was developed for the determination of thiophanate-methyl and carbendazim residues in cucumber and soil by using QuEChERS-high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The residues in the samples were extracted by acetonitrile, cleaned up by developed QuEChERS method, and then analyzed by using LC-MS/MS in multiple reaction monitoring (MRM) mode via positive electrospray ionization with an Agilent ZORBAX SB-C18 column (30 mm×2.1 mm, 5 μm) as the analytical column. The recoveries of thiophanate-methyl spiked at four levels of 0.01, 0.05, 0.1 and 1.0 mg/kg were from 87.3% to 96.0% with the relative standard deviations (RSDs) of 8.0%~9.3% in cucumber, from 88.8% to 93.4% with the RSDs of 5.3%~9.9% in soil; the recoveries of carbendazim spiked at the same levels as those of thiophanate-methyl were from 87.1% to 92.3% with the RSDs of 5.2%~7.5% in cucumber, from 85.8% to 90.9% with the RSDs of 5.3%~13.2% in soil. The method is simple, rapid and characterized with acceptable sensitivity and accuracy to meet the requirements of the pesticide residue analysis. This method is applicable to confirm the residues of thiophanate-methyl and carbendazim in cucumber and soil.

Select

Determination of bisphenol A in plastic parts of small household appliances by liquid chromatography-tandem mass spectrometry ZHANG Yan2, MA Xiaofei2, Lv Pin3, LI Hui2, LU Xiaoyu1* 2012, 30 (01):  95-98.  DOI: 10.3724/SP.J.1123.2011.08030 Abstract ( 1787 )   [Full Text(HTML)] () PDF (162KB) ( 359 )   A method for the determination of bisphenol A in the plastic parts of small household appliances by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. The sample was extracted with accelerated solvent extraction (ASE) and purified by Sep-Pak C18 solid phase extraction. Bisphenol A was separated and detected using LC-MS/MS in negative ion mode with the mobile phases of methanol and water (containing 0.05% ammonia water). The linearity of the method was good in the range of 5 μg/L to 100 μg/L. The recoveries for the spiked sample were from 95.2% to 109.7% at the three levels, 10, 25 and 75 μg/kg. The relative standard deviations were less than 3.8%. The limit of detection was 10 μg/kg. The method is easy-handling, time-saving, sensitive and suitable for the determination of the residual bisphenol A in the plastic parts of household appliances.

Select

Determination of residual organic solvents in flunixin meglumine raw material by headspace gas chromatography HU Huilian* 2012, 30 (01):  99-102.  DOI: 10.3724/SP.J.1123.2011.09009 Abstract ( 1918 )   [Full Text(HTML)] () PDF (152KB) ( 342 )   A method for the determination of five kinds of residual organic solvents in flunixin meglumine raw material was developed by headspace gas chromatography. An HP-FFAP capillary column (30 m×0.32 mm×1.0 μm), a flame ionization detector and the external standard method were used for the separation and quantitative analysis. The effects of equilibrium temperature and equilibrium time on the determination of residual organic solvents were investigated. The good results were obtained in the equilibrium temperature of 90 ℃ and equilibrium time of 30 min. The standard curves were linear in the range of 0.40~7.93 mg/L (r=0.9998) for ethyl acetate, 7.32~146.48 mg/L (r=0.9996) for methanol, 4.53~90.61 mg/L (r=0.9999) for isopropanol, 3.62~72.32 mg/L (r=0.9998) for ethanol and 2.31~46.24 mg/L (r=0.9996) for acetonitrile. The recoveries for the five residual organic solvents were between 95.96% and 100.31% with relative standard deviations (RSDs) (n=6) of 1.97%~3.28%. The detection limits of ethyl acetate, methanol, isopropanol, ethanol and acetonitrile were 0.08, 0.9, 0.2, 0.4 and 0.3 mg/L, respectively. The proposed method was successfully applied to analyze the residual organic solvents in the real sample of flunixin meglumine raw material. The results showed that only isopropanol and ethanol were found in the sample with the contents of 177.44 μg/g and 69.32 μg/g, respectively. The method is rapid, sensitive and accurate for the content determination of residual solvents in flunixin meglumine raw material.

Select

Determination of target compounds in cefoperazone sodium and tazobactam sodium for injection by capillary electrophoresis JIANG Ruiyuan, SUN Guoxiang* 2012, 30 (01):  103-106.  DOI: 10.3724/SP.J.1123.2011.08034 Abstract ( 1737 )   [Full Text(HTML)] () PDF (161KB) ( 323 )   A capillary zone electrophoresis (CZE) method was developed for the simultaneous determination of cefoperazone sodium and tazobactam sodium in the injectable powder of cefoperazone sodium and tazobactam sodium with hydrochlorothiazide as the internal standard. The operation was carried out on a quartz capillary (75 cm×75 μm i.d., 63 cm effective length). The electrophoretic conditions were as follows: 40 mmol/L borax solution as the back ground electrolyte (BGE), 12.0 kV applied voltage, 220 nm as the detection wavelength; the sample solution was injected by hydraulic pressure for 10 s at the height of 10 cm. The cefoperazone and tazobactam showed good linear relationship in the ranges of 0.25~3.96 g/L and 0.062~0.99 g/L with the correlation coefficients of 0.9995 and 0.9996, respectively. The relative standard deviations of relative peak areas were less than 3%. The preparation was stable in 208 min. The recovery results met the methodology requirements. The method is simple, rapid, reproducible, and suitable to control the quality of cefoperazone sodium and tazobactam sodium injectable powder.

Select

Determination of glyoxalate and oxalate by capillary zone electrophoresis GUAN Jin*, WANG Huize, REN Liyan, NIU Qiuling 2012, 30 (01):  107-110.  DOI: 10.3724/SP.J.1123.2011.08055 Abstract ( 1784 )   [Full Text(HTML)] () PDF (138KB) ( 279 )   A method for the simultaneous determination of glyoxalate and oxalate by capillary zone electrophoresis (CZE) was developed. The influences of type, concentration and pH of the running buffer, and the applied voltage on separation were investigated. Glyoxalate and oxalate were separated within 11 min under the conditions of 20 mmol/L borax-5.5 mmol/L potassium hydrogen phthalate (pH 9.0), applied voltage of 20 kV, and detected wavelength of 212 nm. The calibration curves of glyoxalate and oxalate showed good linearity in the ranges of 0.8~20 g/L and 1.2~20 g/L, respectively. The correlation coefficients were 0.9993 and 0.9975, respectively. The limits of detection for glyoxalate and oxalate were 0.2 and 0.4 g/L (S/N=3), respectively. The average recoveries at three spiked levels were 98.3%~102.5% with acceptable relative standard deviations of 0.35%~0.61%. This method is simple, low cost and high performance. The method was successfully used for the determination of glyoxalate and oxalate in real samples, and the assay results were satisfactory.