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Chinese Journal of Chromatography
2006, Vol. 24, No. 3
Online: 30 May 2006

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Simultaneous Determination of Twelve Glucocorticoids Residues in Milk by Ultra Performance Liquid Chromatography-Electrospray Tandem Mass Spectrometry CUI Xiaoliang, SHAO Bing, ZHAO Rong, MENG Juan, TU Xiaoming 2006, 24 (3):  213-217.  Abstract ( 2681 )   [Full Text(HTML)] () PDF (2962KB) ( 1708 )   A comprehensive analytical method based on ultra performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-MS/MS) with negative mode has been developed for the simultaneous determination of twelve glucocorticoids residues in milk. The multi-reaction monitoring mode was employed for the determination. Milk samples were extracted by sonication in a methanol/acetate buffer (pH 5.20) solution, and then defatted with n-hexane. Sample concentration and purification were performed using Oasis HLB, Sep-pak silica and Sep-pak amino-propyl solid phase extraction cartridges. The separation was performed on a Waters ACQUITY UPLCTM BEH C18 column (100 mm×1.0 mm i.d., 1.7 μm) with gradient elution using methanol and water (containing 0.1% formic acid) at a flow rate of 0.1 mL/min. Identification of the glucocorticoids was done using retention times and the distribution of diagnostic ion pairs. Quantification of the glucocorticoids was based on the peak areas of the parent ion and a fragment ion with a higher signal. The limits of detection (LOD) of the method were from 0.02 to 0.38 μg/kg and the limits of quantification (LOQ) ranged from 0.07 to 1.27 μg/kg. Average recoveries for the twelve glucocorticoids (spiked at the levels of 2 and 0.4 μg/kg) ranged from 69.3% to 94.3%, with relative standard deviations between 3.5% and 16.7%. Routine tests showed that the method is fast, sensitive and specific for the determination of glucocorticoids residues in milk.

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Preparation and Quantitative Analysis of Methyl Phenyl Carbonate Standard Sample XING Aihua, ZHANG Minqing, HE Zhimin, ZHANG Jianping 2006, 24 (3):  218-220.  Abstract ( 2579 )   [Full Text(HTML)] () PDF (178KB) ( 942 )   The preparation and quantitative analytical method for high-purity methyl phenyl carbonate (MPC) was developed. Dimethyl carbonate（DMC） and diphenyl carbonate (DPC) were firstly used as reactants to synthesize MPC catalyzed by TiO2/SiO2 because the disproportionation of MPC is reversible and the reverse reaction is thermodynamically favorable. The high-purity MPC standard sample was obtained by reduced pressure distillation and the removal of minor phenol with dilute sodium hydroxide solution. The qualitative analysis by gas chromatography-mass spectrometry （GC-MS） showed there were minor phenol and diphenyl carbonate in the MPC sample. The mass percent concentration of water in the MPC sample was 0.26%, which was determined by Karl Fischer titration. A gas chromatographic method with an OV-101 capillary column was established for quantifying the minor phenol and DPC in the MPC sample. The quantitative results showed the mass concentrations of phenol and DPC were 2.04% and 1.59%, respectively. The difficulty to analyze MPC, the intermediate product of the transesterification of DMC and phenol, was solved with the self-made MPC standard sample.

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Multiresidue Determination of Organophosphorus Pesticide Residues in Vegetables and Fruit by Gas Chromatography-Negative Ion Chemical Ionization-Mass Spectrometry LIN Zhuguang, FAN Yulan, MA Yu, JIN Zhen, TAN Jun, CHEN Meiyu, CHEN Zhaobin, TU Fengzhang, LIU Yong 2006, 24 (3):  221-227.  Abstract ( 2613 )   [Full Text(HTML)] () PDF (1121KB) ( 867 )   An analytical method of gas chromatography coupled with negative ion chemical ionization-mass spectrometry for simultaneous determination of nine organophosphorus pesticide residues in vegetables and fruit has been developed, and the negative ions structure and partition mechanism of the nine organophosphorus pesticides were interpreted. Meanwhile, the matrix effect for sample analysis was discussed, and matrix-matched calibration for quantification was introduced to reduce the matrix effect in this method. Pesticides were extracted from sample with ethyl acetate in an ultrasonic bath, then determined by gas chromatography-mass spectrometry operated in negative chemical ionization mode and quantified in selective ion monitoring mode, and ethion was used as an internal standard. The detection limits of the method were 0.12-1.0 μg/kg for the nine organophosphorus pesticides, and the relative coefficients were higher than 0.9993. A blank sample (tomato) was spiked at 100, 400, 800 μg/kg for each pesticide, and the recoveries were determined to be from 78% to 126% with relative standard deviations from 0.58% to 14.7% for the pesticides.

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Analysis of Pesticide Multiresidues in Rice by Gas Chromatography-Mass Spectrometry Coupled with Solid Phase Extraction LIU Pengyan, LIU Qingxue, MA Yusong, LIU Jinwei, JIA Xuan 2006, 24 (3):  228-234.  Abstract ( 2303 )   [Full Text(HTML)] () PDF (711KB) ( 911 )   A new analytical method was developed to simultaneously determine multiple pesticide residues in rice including organophosphorus, organochlorine, carbamate and pyrethroid. First, the solvents for pesticide extraction were selected for optimization. Eight solvents were screened to find that the extraction efficiency with dichloromethane was the best. Second, clean-up was performed by solid phase extraction using a Florisil cartridge. Various mixtures of hexane and acetone were tested to show that the mixture of hexane-acetone (4∶1, v/v) had the best performance. The clean-up helped the sample purification significantly. The prepared sample was analyzed using gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring （SIM） mode. The pesticides were identified with retention time and selected ions and their relative abundances , and they were quantified based on extract of spiking standards in a blank sample. The limits of detection (LODs) were evaluated on the values of the lower concentration fortified sample under the signal-to-noise ratio of 3∶1. The recoveries and relative standard deviations （RSDs） were checked by adding pesticide standard solution at two levels to untreated samples, and the triplicate analysis of the samples were carried out for each spiked level. The LODs were at μg/kg level. The average recoveries of most pesticides were from 75% to 120 %. The RSDs were less than 10.4%(n=3). These results indicated that this method is simple, rapid, sensitive for the simultaneous determination requirements of multiple pesticide residues in rice.

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Determination of Selenomethionine in Selenium-Enriched Yeast by Gas Chromatography-Mass Spectrometry GAO Jianzhong, HUANG Kehe, QIN Shunyi 2006, 24 (3):  235-238.  Abstract ( 2398 )   [Full Text(HTML)] () PDF (220KB) ( 877 )   A method has been developed for the determination of selenomethionine in selenium-enriched yeast by gas chromatography-mass spectrometry （GC-MS）. Three extraction methods were compared for extraction efficiency of selenomethionine from the samples. Selenomethionine in the samples was extracted for 24 h with proteinase in Tris buffer. The selenomethionine was derivatized with butanol and trifluoroacetic acid （TFA）. The derivatization was accomplished in two steps, starting with the esterification of the carboxyl group of the seleno-amino acid using butanol, followed by the acylation of the amino group with trifluoroacetic acid anhydride. The selected ion for monitoring selenomethionine was at m/z 349. The instrument operating conditions were optimized. The samples were analyzed by GC-MS with external standard method. Standard GC-MS chromatograms and mass spectra for selenomethionine were also obtained. The method was proved to be accurate and reliable. The recoveries of 98.5%-103.7% with relative standard deviations （RSDs） of 0.9%-2.4% (n=6) and the correlation coefficient of 0.9978 were obtained. The detection limit of selenomethionine for the method was 0.5 mg/L （S/N=3） and the selenomethionine contents of real sample was given.

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Determination of Organic Acids Exuded from Plant Roots by High Performance Liquid Chromatography WANG Ping, ZHOU Rong 2006, 24 (3):  239-242.  Abstract ( 2579 )   [Full Text(HTML)] () PDF (186KB) ( 1467 )   A simple and highly sensitive method was developed for the determination of organic acids exuded from plant roots by high performance liquid chromatography with ultraviolet (UV) detection. The root exudate was passed through cation and anion exchange resin columns subsequently. The eluant was then concentrated in a rotary evaporator. The residue was dissolved in dilute HClO4 solution at pH 2.1. The separation was performed on a Bio-Rad Aminex HPX-87H sulfonic column at 50 ℃ with an eluent containing 5 mmol/L H2SO4 at a flow-rate of 0.5 mL/min, and the organic acids were detected at a wavelength of 210 nm by a UV detector. Average recoveries for the root exudates were in the range of 82.0%-96.2% and the detection limits were 1-120 μg/L, and the relative standard deviations (RSD) were 0.67%-3.31% for the seven organic acids. The intra-day precisions were 1.2%-4.7%, and inter-day precisions were 3.3%-10.6%. These results demonstrated that the proposed method is simple, sensitive and reliable for the determination of organic acids in plant root exudates, despite the presence of the particularly complex matrix.

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Specific Depletion of Naringin from Si-Ni-San, a Traditional Chinese Prescription, by an Immunoaffinity Chromatography CHEN Liang, CHEN Ting, XU Qiang 2006, 24 (3):  243-246.  Abstract ( 2214 )   [Full Text(HTML)] () PDF (327KB) ( 733 )   To specifically deplete the compound naringin from Si-Ni-San, a traditional Chinese prescription, an immunoaffinity chromatography column was prepared. The naringin bovine serum albumin (BSA) complex (naringin-BSA) was synthesized to make the complete antigen naringin-BSA. Polyclonal antibody was prepared from the serum of rabbit immunized with naringin-BSA. Then, an immunoaffinity column was made by covalently coupling the polyclonal antibody to CNBr-activated Sepharose 4B and used for depleting naringin from Si-Ni-San. The polyclonal antibody obtained from the rabbit serum was found through enzyme linked immunosorbent assay (ELISA) to show the titer of 1∶30000, the purity of 94% and low cross-reaction rate. The coupling rate of the polyclonal antibody to Sepharose 4B was 87%. By using this column, naringin in Si-Ni-San was selectively depleted from the whole extract. This immunoaffinity column of anti-naringin antibody could be used for specifically depleting naringin from Si-Ni-San and other samples.

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Simultaneous Determination of Four Compounds in Sanjing Shuang-huanglian Oral Liquid by High Performance Liquid Chroma- LIU Lin, SUO Zhirong, ZHENG Jianbin 2006, 24 (3):  247-250.  Abstract ( 2582 )   [Full Text(HTML)] () PDF (356KB) ( 624 )   Chlorogenic acid, caffeic acid, baicalin and luteolin in Sanjing Shuanghuanglian Oral Liquid were simultaneously detected and identified using a high performance liquid chromatography coupled with diode array detection and electrochemical detection (HPLC-DAD-ECD). The separation was performed on a Zorbax SB-C18 column (150 mm×4.6 mm i.d., 5.0 μm). The mobile phase consisted of (A) methanol and (B) methanol-water-acetic acid (50∶50∶1, v/v/v) using a linear gradient elution of 2%A-3%A at 0-3 min, 3%A-25%A at 3-15 min, 25%A-80%A at 15-20 min. The flow rate was 0.8 mL/min. The DAD detection was used at 275 nm. The ECD detection was done at 0.7 V. The column thermostat set at 30 ℃. The limits of detection of the 4 compounds were 1 mg/L for chlorogenic acid, 0.2 mg/L for caffeic acid, 9 mg/L for baicalin, 7 mg/L for luteolin. The average recoveries were between 96.6%-99.6% with relative standard deviations (RSDs) of 2.5%-4.1%. The method is simple, rapid, reproducible and accurate. It can be used for the routine analysis of the four compounds in Shuanghuanglian Oral Liquid.

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Simultaneous Determination of Multiresidual Pesticides in Vegetables and Fruit by High Performance Liquid Chromatography LI Yongxin, SUN Chengjun, ZHAO Jianhong, YANG Liuhua 2006, 24 (3):  251-255.  Abstract ( 2221 )   [Full Text(HTML)] () PDF (406KB) ( 792 )   A high performance liquid chromatographic （HPLC） method for simultaneous determination of 12 pesticides in vegetable and fruit samples was developed and evaluated. The analytical procedure involved in ultrasonic extraction with ethyl acetate, purification using a Florisil SPE column (6 mL, 1000 mg) and n-hexane-dichloromethane (1∶1, v/v). The eluate was blown to dryness under a stream of nitrogen and the residue was dissolved in 0.10 mL of methanol, followed by separation and quantitative analysis by using reversed-phase HPLC with gradient elution for the baseline separation of the 12 pesticides and programmed ultraviolet wavelength shift detection in 32 min. The detection limits of the 12 pesticides ranged from 0.14 to 2.65 ng. The average recoveries ranged from 62.2% to 118.2% with the relative standard deviation （RSD）range of 0.56% -11.8% for the spiked fruit samples, and from 52.1% to 124.6% with RSD range of 0.89%-18.4% for the spiked vegetables. The method was applied to determining multiresidual pesticides in vegetables and fruit for a total of 40 samples. It is concluded that this method is rapid, accurate, sensitive and reproducible for determining trace pesticides in vegetable and fruit samples.

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Determination of T-2 Toxin in Cereal Grains by High Performance Liquid Chromatography with Fluorescence Detection after Immunoaffinity Column Clean-Up and Precolumn Derivatization LI Jun, XU Ye, SUI Kai, WEI Feng, ZHAO Shoucheng, WANG Yuping 2006, 24 (3):  256-259.  Abstract ( 2104 )   [Full Text(HTML)] () PDF (467KB) ( 838 )   A method has been developed for the determination of T-2 toxin in cereal grains by high performance liquid chromatography with fluorescence detection after immunoaffinity column clean-up and precolumn derivatization.The derivatization reaction was used to develop a sensitive, reproducible and accurate method for the determination of T-2 toxin in wheat, corn, barley and rice. T-2 toxin was extracted with methanol-water (80∶20, v/v), purified by immunoaffinity columns containing antibodies specific for T-2 toxin, and quantified by reversed-phase high performance liquid chromatography with fluorescence detection (excitation wavelength, 381 nm; emission wavelength, 470 nm) after derivatization with 1-anthroylnitrile （1-AN） and 4-dimethylaminopyridine (DMAP). ZORBAX Eclipse XDB-C18 column and mobile phase of acetonitrile-water (80∶20, v/v) were used for the analysis. Recoveries from the different cereals spiked with T-2 toxin at levels ranging from 0.01 to 1.5 μg/g were from 79.7% to 94.5%, the relative standard deviations were lower than 7% and the limit of detection was 0.01 μg/g based on a signal-to-noise ratio of 3∶1.

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Determination of Urinary trans, trans-Muconic Acid by High Performance Liquid Chromatography LIU Liwen, SONG Shizhen, HU Xiamin, YE Fangli 2006, 24 (3):  260-262.  Abstract ( 2369 )   [Full Text(HTML)] () PDF (215KB) ( 592 )   A method for the determination of urinary trans, trans-muconic acid (tt-MA)（benzene metabolite） by high performance liquid chromatography （HPLC） was developed. The separation was carried out on a C18 column (Spherisorb C18, 150 mm×4.6 mm i.d., 5 μm) at 25 ℃ with glacial acetic acid-tetrahydrofuran-methanol-water (1∶2∶10∶87, v/v) as mobile phase. Urinary sample was acidified by 2 mol/L hydrochloric acid and pretreated by liquid-liquid extraction using diethyl ether. After removal of diethyl ether with a stream of nitrogen, the residue was re-dissolved in 1 mL of mobile phase for HPLC injection. Good linearity was observed within the range from 0.10 mg/L to 10.00 mg/L (r＝0.9999) and the detection limit was 0.10 mg/L. The average recoveries for tt-MA were 95.1%-100.5%. Relative standard deviations (RSD) for intra-day and inter-day determinations were 4.0%-9.0% and 6.2%-8.8%, respectively. The method was applied to 56 benzene-exposed workers and 24 controll workers. Urinary tt-MA in benzen-exposed workers were significantly higher than that in the control group. They can be correlated with benzene exposure concentrations (P<0.01). This analytical method for tt-MA is sensitive, rapid, and convenient. It is suitable for monitoring of occupational exposure to benzene and toxic kinetics studies.

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Determination of Collagen in Tendon by Reversed-Phase High Performance Liquid Chromatography ZOU Xiaoli, LI Yuanqian, ZENG Hongyan, ZHOU Jian, QIN Tingwu, MO Xiangtao 2006, 24 (3):  263-266.  Abstract ( 2606 )   [Full Text(HTML)] () PDF (373KB) ( 876 )   A method for determining collagen in tendon by reversed-phase high performance liquid chromatography (RP-HPLC) was developed. After hydrolysis with hydrochloric acid, the collagen in samples was decomposed into hydroxyproline which hydroxyproline can be derivatized with 2，4-dinitrochlorobenzene for the determination by HPLC (reversed-phase C18 column, 0.01 mol/L NaAc-HAc（pH 6.0 ）-CH3CN （80∶20, v/v） as mobile phase, detection at 360 nm). The factors influencing hydrolysis, derivatization and HPLC analysis were studied and optimized. Sixty samples were analyzed with the proposed method. The linear range was from 3 μg/L to 100 mg/L and the detection limit was 3 μg/L. The relative standard deviation (RSD) of determination was 1.95%. The recoveries of spiked samples were 98.4%-110.8%. The results show that the method is sensitive, accurate and suitable for tendon determination.

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Determination of Triazines in Surface Water Using Solid Phase Extraction-High Performance Liquid Chromatography LI Zhu, CHEN Ling, GAO Hongwen, DONG Lixian, ZHAO Jianfu 2006, 24 (3):  267-270.  Abstract ( 2076 )   [Full Text(HTML)] () PDF (416KB) ( 860 )   A method was developed to monitor triazines in surface water using the combination of solid phase extraction (SPE) and high performance liquid chromatography. Four different SPE cartridges were tested for extracting six triazines, including atrazine (A), simazine (S), prometryn (P), desethylatrazine (DEA), 2-hydroxyatrazine (OHA) and desisopropylatrazine (DIA), and finally ENVI-18 was selected as optimal. The method for solid phase extraction was further systematically studied for details. Optimal results of orthogonal design were determined as follows: pH 6, 5 mL methanol as eluting solvent, and no methanol added into water sample before extraction. The detection limits of six triazines were 0.14 μg/L for P, 0.12 μg/L for A, 0.08 μg/L for S, 0.08 μg/L for DEA, 0.10 μg/L for OHA and 0.18 μg/L for DIA. This method was applied for environmental aquatic samples, and the results showed that the concentration of prometryn in a lake was detected as (9.33±0.27) μg/L, as well as the concentrations of atrazine and prometryn in a river were detected as (5.28±0.43) μg/L and (7.12±0.54) μg/L respectively.

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Separation and Purification of Phosphatidylcholine in Swine Liver and Its Inhibition Effect on Proliferation of Rat Hepatoma Cells WANG Liang, LIU Cuiping, JIA Dan, ZOU Wei 2006, 24 (3):  271-274.  Abstract ( 2441 )   [Full Text(HTML)] () PDF (1028KB) ( 768 )   Phosphatidylcholine (PC) in crude phospholipids from swine liver was separated and purified by using Al2O3 column chromatography with 95% alcohol as eluent. The purity was determined by thin layer chromatography on GF254 silica gel plate and with chloroform-methanol-water (65∶25∶4，v/v) as developing agent. The results showed that PC was completely separated from phosphatidylethanolamine (PE) by the elution with 95% alcohol, and its purity and yield reached more than 90% and 80% with a elution volume of 225 mL, and 87.6% and 87.3% with a elution volume of 425 mL respectively. The effect of the PC with different concentrations on the proliferation of rat hepatoma cell line (CBRH-7919) was determined by microculture tetrazolium (MTT) assays in vitro and was compared with that of human leukemia cell line K562. Result shows that the PC derived from the liver inhibited the growth of CBRH-7919 cells significantly. It suggested that PC derived from animal liver might function as a specific inhibitor for hepatoma cells in a concentration dependent manner.

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Purification of Plastocynin from Ulva pertusa by Column Chromatography and Analysis of Its N-Terminal Amino Acid Sequence LIU Zhenyu, WU Zujian, LIN Qiying, XIE Lianhui 2006, 24 (3):  275-278.  Abstract ( 2456 )   [Full Text(HTML)] () PDF (299KB) ( 700 )   Protein plastocyanin from a green alga, Ulva pertusa, has been purified. Samples were homogenized in 0.02 mol/L phosphate buffer (pH 7.2) and then centrifuged to remove debris and subjected to ammonium sulfate fractionation (40%-80% saturation). Ion exchange column chromatography with DEAE-Sepharose Fast Flow and gel filtration column chromatography with Sephadex G-75 were then employed for further purification of plastocyanin. Three peaks, A, B and C, were eluted with 0.01 mol/L phosphate buffer, containing a NaCl linear gradient from 0 to 1.0 mol/L at the flow rate of 32 mL/h through DEAE-Sepharose chromatography. The protein fractions containing the plastocyanin were then purified further with Sephardex G-75 column chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophores (SDS-PAGE) is analysis indicates that the protein was purified to homogeneity and its relative molecular mass is 10000. N-terminal amino acid sequence was used to identify the protein. The protein was transblotted to PVDF membrane and N-terminal amino acid sequence was performed via Edman degradation with an automated amino acid sequencer. The 20 N-terminal amino acid residues are AAIVKLGPDDGSLAFVPSKI, which share 85% homology with the 20 N-terminal amino acid sequence of U. prolifera and U. arasakii, and share 90% homology with the ones of U. pertusa formerly reported.

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Purification of Cadmium Ion Binding Metallothionein-3 by Proteinase Digestion on Affinity Chromatographic Column ZHENG Weijuan, YANG Feng, WU Fang, LU Chun, HUA Zichun 2006, 24 (3):  279-283.  Abstract ( 2555 )   [Full Text(HTML)] () PDF (2647KB) ( 747 )   The gene encoding human metallothionein-3 (hMT-3) was synthesized and inserted into the poly-cloning sites of fusion expression vector pALEX, and fused downstream to its glutathione S-transferase (GST) fusion partner. Fusion protein GST-Cd2+-hMT-3 was expressed after isopropyl-β-D-thiogalactopyranoside （IPTG） induction and addition of 0.1 mmol/L CdSO4 into the culture medium, and mainly existed in cellular soluble fraction as revealed by sodium dodecyl sulfate polyacrylamide gel electrophoresis （SDS-PAGE） analysis. Recombinant MT was purified by two purification procedures: “proteinase digestion after purification” method, e.g. by elution of GST-Cd2+-hMT-3 from GST affinity chromatography first, then proteinase digestion and GST affinity chromatographic purification again subsequently; and “proteinase digestion in situ” method, e.g. digestion of GST-Cd2+-hMT-3 directly on the column while its binding to the GST affinity chromatographic resin and collection of Cd2+-MT directly from the flow through fraction after the digestion. It was confirmed that the later procedure exhibited more effective and more convenient by avoiding the conventional elution, dialysis and lyophilization processes and increasing the purity, recovery or yield of the final product. After further purification by a SuperdexTM 75 HR 10/30 column, finally 6-7 mg of Cd2+-hMT-3 was obtained from 3 L of flask culture with the recovery of about 1.8%. SDS-PAGE, amino acid composition and inductively coupled plasma atomic emission spectrometer (ICP-AES) analysis showed that the relative molecular mass of Cd2+-hMT-3 is about 7000, with a purity above 90%. Its amino acid composition is consistent with the expected value of natural hMT-3, particularly no aromatic amino acid and histidine, and the atomic ratio of 21∶（7.5±0.1） for S∶Cd, is also consistent with the theoretical value of 21∶7.

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Inverse Gas Chromatography Used to Study Lubricating Oil Oxidation Mechanism via Changes in Kovats and Flory-Huggins Retention Parameters MOSTAFA Nagy E, EISSA Elham A 2006, 24 (3):  284-289.  Abstract ( 2243 )   [Full Text(HTML)] () PDF (629KB) ( 552 )   Inverse gas chromatographic technique (IGC) was attempted as a new approach to follow the chemical changes that occur during lubricating base oil oxidation. Three groups of the oxidized base oils were prepared at different oxygen flow rates, periods and temperatures according to IP48 method. The corrected retention volumes (VR) were calculated for a series of selected test solutes possessing different functional groups on the oxidized base oils used as stationary phases. Kovats retention index (I), Flory-Huggins interaction parameter (κ∞1,2), and partial molar free energy of solution (ΔG∞L), were calculated for the given test solutes from their VR. The relationships between the I values and the oxidation variables were plotted and discussed. The obtained results were confirmed by potentiometric titration. The study reveals that the magnitudes of variation of I, κ∞1,2 or ΔG∞L retention parameters depend on the oxidation degree of the base oil. Large differences between the I values permit discrimination between the different oxidation steps.

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Determination of Organophosphorous Pesticide Residues in Red Wine by Solid Phase Microextraction-Gas Chromatography HU Yuan, LIU Wenmin, ZHOU Yanming, GUAN Yafeng 2006, 24 (3):  290-293.  Abstract ( 2393 )   [Full Text(HTML)] () PDF (405KB) ( 984 )   A method for the determination of 12 organophosphorus pesticide residues (OPs) in red wine by fiber solid phase microextraction (SPME) coupled with gas chromatography (GC) was developed and validated. The SPME phase was prepared by sol-gel technology of physical incorporation. The extraction conditions were optimized with the results of stirring rate of 1250 r/min, NaCl mass concentration of 150 g/L, and extraction time of 30 min. With the sample volume of 25 mL, the relative standard deviations (RSD) of peak areas for most of OPs were below 5%, and the detection limits of OPs were in the range of 5 ng/L-0.38 μg/L. It can be seen from the results that this method has the potential to analyze OPs in other beverages and soft drinking materials.

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Fast Determination of Andrographolide and Dehydroan-drographolide in Xiaoyanlidan Tablets by Microemulsion Electrokinetic Chromatography ZHAO Yanfang, LUO Xingping, MING Yongfei, ZHANG Hongli, LI Xiujuan, CHEN Liren, LI Yongmin 2006, 24 (3):  294-297.  Abstract ( 2096 )   [Full Text(HTML)] () PDF (480KB) ( 677 )   A microemulsion electrokinetic chromatography (MEEKC) method for the determination of andrographolide and dehydroandrographolide in Xiaoyanlidan Tablets was established. The MEEKC method involved the use of sodium dodecyl sulfate (SDS) as surfactant, ethyl acetate as organic solvent and 1-butanol as co-surfactant. The effects of several factors such as the acidity and concentration of borate buffer, SDS and 1-butanol contents were investigated. The optimized composition (by mass) of microemulsion system are 0.5% ethyl acetate-0.6% SDS-6.0% 1-butanol-92.9% 30 mmol/L sodium tetraborate buffer (pH 9.5). This system allowed a useful and reproducible separation of the analytes to be achieved in less than 6 min. The proposed method is a simple, fast and sensitive method for the determination of andrographolide and dehydroandrographolide in Xiaoyanlidan Tablets.

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Determination of Trace Haloacetic Acids in Drinking Water Using Ion Chromatography Coupled with Solid Phase Extraction SUN Yingxue, HUANG Jianjun, GU Ping 2006, 24 (3):  298-301.  Abstract ( 2275 )   [Full Text(HTML)] () PDF (320KB) ( 765 )   The combined solid phase extraction (SPE)-ion chromatography (IC) method was developed for the analysis of trace haloacetic acids (HAAs) in drinking water. The tested HAAs included monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), trichloroacetic acid(TCAA), monobromoacetic acid (MBAA) and dibromoacetic acid (DBAA). For trace determination of HAAs in real drinking water samples, conditions of LiChrolut EN SPE cartridge were investigated for HAAs preconcentration and matrix elimination. Elution was carried out by 2 mL of sodium hydroxide (10 mmol/L) with the flow rate of 2 mL/min. The Dionex IonPac AS16 column (250 mm×4 mm i.d.), a high capacity and hydroxide-selective anion-exchange column designed for the determination of polarizable anions, was chosen for chromatographic separation. HAAs were analyzed with a concentration gradient of NaOH with the flow rate of 0.8 mL/min and detected by suppressed conductivity. A 500 μL sample loop was used. The detection limits of this SPE-IC method for MCAA, DCAA, DBAA and TCAA were 0.38-1.69 μg/L and MBAA was 12.5 μg/L under 25-fold preconcentration. The results demonstrate that the method is suitable for the analysis of trace haloacetic acids in drinking water.

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Determination of Trace Bromate in Drinking Water by Ion Chromatography with Suppressed Conductivity Detection Ying Bo, Li Shumin, Yue Yinling, E Xueli 2006, 24 (3):  302-304.  Abstract ( 2491 )   [Full Text(HTML)] () PDF (233KB) ( 792 )   Bromate is a common disinfection by-product produced from the ozonation of source water containing bromide. An ion exchange chromatographic method with suppressed conductivity detection for the determination of trace bromate in drinking water was developed. The separation of the bromate in drinking water was achieved on a Metrosep A Supp 5 anion exchange column and a Metrosep A Supp 4/5 Guard column with a carbonate eluent. A new dual suppressed system, an MSMⅡchemical suppressor combined with a CO2 suppressor, was used to suppress the background conductivity, and to improve the detection limit of bromate. Ion chromatographic experiments were carried out by using a Metrosep A Supp 5 anion exchange column with a suppressed conductivity detector and an eluent of 3.2 mmoL/L Na2CO3-1.0 mmol/L NaHCO3 at a flow rate of 0.65 mL/min. This method had good linearity (r=0.9999) in the range of 5-100 μg/L and high precision (relative standard deviation (RSD)＜4%) for three concentration levels of bromate. The average recoveries of the spiked samples including tap water, pure water and mineral water were 96.1%-107%, and the detection limit for bromate was 0.50 μg/L. This method has a simple operation procedure, good separation results, high sensitivity and good repeatability. It can be used as a standard method for the determination of bromate in drinking water.

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Preparation and Evaluation of Molecularly Imprinted Stationary Phase Used for Thin-Layer Chromatography RONG Fei, LI Ping, FENG Xiaogang, YUAN Chunwei, FU Degang 2006, 24 (3):  305-308.  Abstract ( 2345 )   [Full Text(HTML)] () PDF (189KB) ( 1796 )   Thin-layer chromatography (TLC) using molecularly imprinted polymers (MIPs) as chiral stationary phases (CSPs ) was applied to the determination of enantiomers of mandelic acid and its derivatives. In preparation of MIPs, L-mandelic acid, L-2-chloromandelic acid and L-4-chloromandelic acid were employed as templates; acrylamide (AM) and ethylene glycol dimethacrylate (EGDMA) were used as functional monomer and cross-linker respectively. With the development system of acetonitrile-5%acetic acid, the racemates of templates were completely separated on the CSPs, the chiral separation factor α were 1.45, 1.62 and 1.56, respectively. Furthermore, the CSPs were able to resolve the racemates of template’s derivatives. The relationship between the chemical structure of the analytes and chiral recognition of the CSPs was also investigated. This method provides a rapid, sensitive and convenient way of analyzing and determining the enantiomers of chiral compounds.

专论综述

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Separation and Recognition of Biomacromolecule by Molecular Imprinting Technique ZHENG Chao, GAO Ruyu, ZHANG Yukui 2006, 24 (3):  309-314.  Abstract ( 2590 )   [Full Text(HTML)] () PDF (7786KB) ( 1005 )   Molecular imprinting technique is a novel technique based on mimicking specific action of antibody-antigen. The emergence and the development of the technique are reviewed in this article. The focuses of this article include the introductions of the synthesis conditions, the comparisons of the various approaches on preparation methods as well as the recognition mechanisms of the biomacromolecule imprinted polymers. The primary synthetic methods include the embed technique, the surface imprinting procedure and the epitope approach. The epitope approach is based on using a short peptide as a template that represents only part of a larger peptide or protein, which in turn can be recognized by the synthesized polymer. This approach for the development of the biomacromolecule imprinted polymers selective to proteins is attractive from an economic viewpoint: a small peptide is usually less expensive, and the quantity necessary for the polymer preparation is more readily available than that of the corresponding protein. In the end, the limitations and the prospective applications of this biomacromolecular imprinted technique are also discussed.

技术应用

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Analysis of Main Sterols in Tobacco by Gas ChromatographyMass Spectrometry with Solvent Extraction XU Yanjuan, ZHONG Kejun, BAI Changmin，HUANG Jianguo, TANG Wanying，LU Xin, LU Guo, XU Guowang 2006, 24 (3):  315-316.  Abstract ( 1839 )   [Full Text(HTML)] () PDF (240KB) ( 747 )

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Determination of Tetrodotoxin by HPLC with Ultraviolet Detection and Fluorescence Detection CUI Jianzhou, SHEN Xueyan ，GONG Qingli, GU Qianqun 2006, 24 (3):  317-317.  Abstract ( 2369 )   [Full Text(HTML)] () PDF (94KB) ( 871 )

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Enantiomeric Separation of 1,4-Dihydro-5-Methoxycarbonyl-2,6-Dimethyl-4-(3-Nitrophenyl)-3-Pyridinecarboxylic Acid Enantiomers LI Kun, WANG Hairong, WANG Hai, DU Yumin 2006, 24 (3):  318-318.  Abstract ( 2388 )   [Full Text(HTML)] () PDF (625KB) ( 699 )

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Determination of Six Water-Soluble Vitamins and Caffein in Health Food by High Performance Liquid Chromatography WU Shujun, ZHUANG Zhihui，ZHU Mengli, XU Xiaoyan 2006, 24 (3):  319-319.  Abstract ( 2530 )   [Full Text(HTML)] () PDF (79KB) ( 889 )

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Determination of Ractopamine in Animal Urine by SPE-HPLC YING Yongfei, PI Xionge，CHEN Huihua, ZHU Congying 2006, 24 (3):  320-320.  Abstract ( 2611 )   [Full Text(HTML)] () PDF (95KB) ( 902 )

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Determination of Organophosphorus Pesticide Residues in Greasy Wool by Gas Chromatography JIANG Haining, WU Xiongying, YANG Juan，FEI Xudong, SHI Li, TANG Minfeng 2006, 24 (3):  321-321.  Abstract ( 1953 )   [Full Text(HTML)] () PDF (47KB) ( 707 )

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Preparation of Particle-Fixed Monolithic Microbore Column for Electrochromatography QU Qishu, LU Xiao, TANG Xiaoqing，LIU Yin, HU Xiaoya 2006, 24 (3):  322-322.  Abstract ( 2119 )   [Full Text(HTML)] () PDF (256KB) ( 690 )

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Application of Microemulsion to Thin Layer Chromatographic Analysis of Flavonoid Composition in Traditional Chinese Medicine ZHOU Xuan, SONG Fenyun, ZHONG Zhaojian 2006, 24 (3):  324-324.  Abstract ( 1950 )   [Full Text(HTML)] () PDF (45KB) ( 794 )