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List of Issues

    Chinese Journal of Chromatography
    2007, Vol. 25, No. 4
    Online: 30 July 2007

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    Communications

    Detection of Multi-Phosphopeptide Sites Using Microcolumn High Performance Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry

    WANG Hui, DUAN Jicheng, YUAN Huiming, ZHANG Lihua, ZHANG Weibing, ZHANG Yukui
    2007, 25 (4):  453-456. 
    Abstract ( 2251 )   [Full Text(HTML)] () PDF (373KB) ( 732 )  
    A novel detection method for the analysis of multi-phosphopeptides using microcolumn high performance liquid chromatography-electrospray ionization tandem mass spectrometry (μHPLC-ESI-MS/MS) was proposed by the dephosphorylation treatment of alkaline phosphatase (AP). After the selective enrichment by a microcolumn packed with TiO2, phosphopeptides from the tryptic digests of β-casein were dephosphorylated by AP. Through the removal of phosphate groups, the detection of multi-phosphopeptides according to the non-phosphorylated ones was achieved by ESI-MS/MS. By comparing the chromatograms before and after the AP treatment, mono-phosphopeptides were identified based on the relative molecular mass (Mr) difference of 80. Furthermore, since more peaks appeared after the treatment, the existence of multi-phosphopeptides was proven. By controlling the treatment procedure, the partial dephosphorylation of multi-phosphopeptides was performed, and the multi-phosphorylated sites of the digest of β-casein were found to be on serine residues at the possible sites of 17, 18 and 19.
    专论综述
    Advances in Catecholamine Analysis in Biological Samples
    GU Qun, SHI Xianzhe, XU Guowang
    2007, 25 (4):  457-462. 
    Abstract ( 2547 )   [Full Text(HTML)] () PDF (248KB) ( 1116 )  
    Catecholamines are important neurotransmitters in human organism. Catecholamine levels in plasma and urine are utilized to diagnose hypertension, pheochromocytoma and neuroblastoma. This review reports different analytical methods for catecholamines, such as high performance liquid chromatography, capillary electrophoresis, mass spectrometric detection, electrochemical detection, chemiluminescence detection and fluorescence detection.
    Articles
    Preparation of Capillary Electrophoresis Column Physically Coated with Hyperbranched Polyesters and Its Application in the Separation of Basic Proteins
    SHOU Chongqi, ZHANG Zhiliang, KANG Jiefen
    2007, 25 (4):  463-467. 
    Abstract ( 1801 )   [Full Text(HTML)] () PDF (555KB) ( 734 )  

    Two series of hyperbranched polyesters were synthesized using pentaerythritol as the core by one-step and pseudo-step procedures. The molecular structures of the hyperbranched polyesters were characterized using infrared spectrum and hydroxyl value. Due to their low viscosity, the hyperbranched polyesters were easily coated on the inner surface of the fused-silica capillary by physical adsorption. The adsorption behavior of this capillary electrophoresis column coated with polyesters was investigated by the separation of three basic proteins. The electro-osmotic flow and the capability for the separation of the basic proteins were studied. It was found that the coatings of hyperbranched polyesters could significantly reduce the electro-osmotic flow and suppress the protein adsorption onto the inner surface of the fused-silica capillaries in the pH range of 3.0-7.0. Three basic proteins were effectively separated at pH = 5 on the column coated with the hyperbranched polyesters, with the separation efficiency being 105 plates/m. The experimental results also showed that the separation efficiency and the resolution on columns coated with hyperbranched polyesters by pseudo-step procedure were much better than those by one-step procedure.

    Differentiation of Species of Blue Inks for Roller-Ball Pen and Determination of Relative Writing Ages by High Performance Capillary Electrophoresis
    WANG Yuanfeng, WANG Jinghan, YAO Lijuan
    2007, 25 (4):  468-472. 
    Abstract ( 2434 )   [Full Text(HTML)] () PDF (2312KB) ( 805 )  

    Traces of 13 blue roller-ball pen inks were identified by high performance capillary electrophoresis (HPCE) with 0.03 mol/L borate and 10%(in volume) methanol as buffer at the voltage of 15 kV and the temperature of 25 ℃. Samples could be classified into 3 major groups and 5 subgroups by UV detection results and 4 species by visible detection results. The analytical results with different wavelength lights could be used to cross confirm the ink species. The aging effect was studied for 3 samples stored in darkness, and the relative ages were determined based on the relative quantities of some components. In addition, no effect of the matrix of paper was found on the results.

    Rapid Detection of Three Foodborne Pathogenic Bacteria by Multiplex Polymerase Chain Reaction-Capillary Electrophoresis with Laser Induced Fluorescence Detector
    MAO Hongxia, LI Yuanqian, PEI Xiaofang, HE Chao, QU Lingli
    2007, 25 (4):  473-477. 
    Abstract ( 2263 )   [Full Text(HTML)] () PDF (320KB) ( 725 )  
    A method for monitoring foodborne pathogenic bacteria by multiplex polymerase chain reaction (PCR)-capillary electrophoresis (CE) with a laser induced fluorescence detector was developed. Three sets of primers were designed to amplify the gene segments of uidA gene in E.coli.O157:H7, invA gene in salmonella and ipaH gene in Shigella, individually. The multiple PCR system and the separation conditions of CE were optimized. Using a capillary coated with linear polyacrylamide and sieving buffer of 7.0 g/L methyl cellulose (MC) under 8.3 kV of electric voltage, the proposed method was able to simultaneously detect the PCR products of specific genes existing in the three kinds of pathogenic bacteria within 22 min. The relative standard deviations of migration time for the detected DNA fragments were ranging from 1.47% to 2.07%. In comparison with agarose gel electrophoresis, the proposed method is rapid, sensitive and accurate.
    Chiral Separation of Doxazosin and Its Intermediate by Capillary
    Electrophoresis Using Tetramethylammonium Hydroxide to Control Electroosmotic Flow
    CHENG Yushan, YANG Xiaolan, YU Yu
    2007, 25 (4):  478-481. 
    Abstract ( 2387 )   [Full Text(HTML)] () PDF (363KB) ( 658 )  
    A capillary electrophoretic method for the enantiomeric separations of doxazosin and its intermediate was developed. Several tetraalkylammonium reagents were examined for controlling the electroosmotic flow in order to improve resolution of the enantiomers. Tetramethylammonium hydroxide (TMB) was found more suitable than tetrabutylammonium hydroxide (TAB) or hexadecyltrimethylammonium bromide (CTAB) for the enantiomer separation. In addition, the effects of the pH value, the separation voltage and the concentration of the sodiumdihydrogen phosphate on the chiral separation were investigated. A buffer containing 60 mmol/L sodium dihydrogen phosphate (pH 2.2), 30 mmol/L TMB and 12 mmol/L β-cyclodextrin (β-CD) resulted in the baseline separation of the doxazosin enantiomers and its intermediate enantiomers. It showed that the presence of TMB was essential in some chiral separations that were previously not achieved by only using the β-CD as a chiral selector.
    Numerical Analysis on the Influence Factors of Sample Stacking in Capillary Electrophoresis
    CAO Jun, HONG Fangjun, CHENG Ping
    2007, 25 (4):  482-485. 
    Abstract ( 2073 )   [Full Text(HTML)] () PDF (322KB) ( 626 )  

    Sample stacking in capillary electrophoresis can concentrate sample species through the electrical field strength gradient caused by the inhomogeneous buffer concentration field in capillary. The factors that affect the sample stacking process have been analyzed in detail by using a 1-D mathematic model. It was found from the simulation results that the electrical charge number and the electrical charge sign of sample particles can affect the electrophoretic velocity, which in turn has an important influence on the stacking process. The electrical potential can affect the migration time of sample particles to reach detection window, and the initial length of sample plug has significant influence on the maximal sample concentration after stacking and the time to get the optimal stacking effect. The results obtained are helpful to the improvement of the sample stacking technique.

    Determination of Glyphosate and Aminomethylphosphonic Acid Residues in Foods Using High Performance Liquid chromatography-Mass Spectrometry/Mass Spectrometry
    LI Bo, DENG Xiaojun, GUO Dehua, JIN Shuping
    2007, 25 (4):  486-490. 
    Abstract ( 2722 )   [Full Text(HTML)] () PDF (343KB) ( 1505 )  

    A method for the determination of glyphosate (PMG) and aminomethylphosphonic acid (AMPA) residues in plant products, such as rice, wheat, vegetables, fruits and tea, pig and chicken muscles, aquatic products, chestnut, honey, etc., was developed using high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). In this method, PMG and AMPA were extracted with water from samples, defatted using an extraction step with dichloromethane, and purified using a cation-exchange (CAX) solid phase extraction cartridge. Then, these were derived using fluorenylmethylchloroformate (FMOC-Cl) in borate buffer for subsequent HPLC-MS/MS analysis. Isotope-labeled PMG 1,2-13C15N was used as the internal standard for the quantitative analysis of two residues. For all samples, the recoveries ranged from 80.0% to 104% and the relative standard deviations (RSDs) ranged from 6.7% to 18.2%. The limit of quantification (LOQ) was determined to be 0.05 mg/kg with a linear range of 0.20-10 μg/L. It is demonstrated that this method is reliable and sensitive for the analysis of PMG and APMA with low concentrations in foods.

    Determination of 16 Quinolone Residues in Animal Tissues Using High Performance Liquid Chromatography Coupled with Electrospray Ionization Tandem Mass Spectrometry
    YUE Zhenfeng, LIN Xiuyun, TANG Shaobing, CHEN Xiaoxia, JI Caini, HUA Honghui, LIU Yu
    2007, 25 (4):  491-495. 
    Abstract ( 2226 )   [Full Text(HTML)] () PDF (499KB) ( 1385 )  

    A confirmative method was developed with high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC-MS/MS) to simultaneously detect 16 quinolone residues in animal tissues, which included nalidixinic acid, oxolinic acid, flumequine, norfloxacin, enoxacin, ciprofloxacin, lomefloxacin, danofloxacin, enrofloxacin, ofloxacin, sarafloxacin, difloxacin, marbofloxacin, pefloxacin, sparfloxacin and orbifloxacin. In the method, the 16 residues were extracted with acidified acetonitrile, cleaned-up with hexane, and concentrated with a rotary evaporator. Then the reconstituted sample solution was analyzed using HPLC-MS/MS in positive mode, with a Inertsil C8-3 column as the analytical column. The method was validated at 10, 50 and 100 μg/kg. The validation results were as follows: the linear ranges were from 10 to 100 μg/kg; the overall recoveries were from 62.4% to 102% with the relative standard deviations of 1.4%-11.9%. The method is simple, rapid, and accurate, and its performance could meet the requirements of the domestic and international legislation. The method is applicable to simultaneously confirm multi-residues of quinolones in animal tissues such as chicken muscle, chicken liver and fish muscle.

    Separation and Identification of Chlorogenic Acid and Related Impurities by High Performance Liquid Chromatography-Tandem Mass Spectrometry
    TIAN Chenxu, XU Xiaoping, LIAO Liyun, ZHANG Jie, LIU Jing, ZHOU Sha
    2007, 25 (4):  496-500. 
    Abstract ( 2576 )   [Full Text(HTML)] () PDF (762KB) ( 1321 )  

    A method using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established for analysis and identification of chlorogenic acid along with its related impurities. A Gemini C18 HPLC column (4.6 mm×150 mm,5 μm) was used with acetonitrile-water ( containing 0.1% formic acid) (8∶92, v/v) as mobile phase. Eight related impurities of chlorogenic acid were identified and their structures were determined by using on-line HPLC-MS/MS and photodiode array detector (DAD). The method is quick, simple and can be used directly to identify the structure of unknown trace substances in the sample of chlorogenic acid.

    Synthesis and Oxidative Refolding of an N-Terminal Truncate of Jingzhaotoxin-V and Characterization of Its Activities of Sodium Channels
    QUAN Miaohua, ZENG Xiongzhi, PI Jianhui, DENG Meichun, LIANG Songping
    2007, 25 (4):  501-504. 
    Abstract ( 2002 )   [Full Text(HTML)] () PDF (381KB) ( 566 )  

    An N-terminal tyrosine residue truncate of Jingzhaotoxin-V (Y1-JZTX-V) was synthesized by solid-phase chemical methods using Fmoc-protected amino acids. Reversed-phase high performance liquid chromatography (RP-HPLC) and matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) were used to monitor the oxidative refolding of Y1-JZTX-V to find the optimal renaturation conditions of the synthetic linear peptide. When Y1-JZTX-V (0.05 mg/L) was dissolved in 0.1 mol/L Tris-HCl buffer containing 1 mmol/L GSH and 0.1 mmol/L GSSG at pH 7.50 and 4 ℃, the best renaturation yield of the truncate toxin was obtained. Under the whole-cell patch-clamp mode, Y1-JZTX-V could inhibit tetrodotoxin-resistant (TTX-R) and tetrodotoxin-sensitive (TTX-S) sodium currents in adult rat dorsal root ganglion neurons with IC50 values of 160 nmol/L and 39.6 nmol/L, respectively. The inhibition potentiality of Y1-JZTX-V on TTX-S sodium currents was almost the same as the natural JZTX-V, while that on TTX-R sodium currents was obviously weakened. The IC50 value of Y1-JZTX-V on TTX-R sodium currents was 5.8 times as many as that of natural JZTX-V. Present findings indicated that the first tyrosine residue (Y1) in the N-terminal of JZTX-V was involved in the binding activities of JZTX-V to TTX-R sodium channels.

    Synthesis of Periodic Mesoporous Ethanesilica and Its Application in High Performance Liquid Chromatography
    ZHU Guiru, YANG Qihua, LI Can
    2007, 25 (4):  505-508. 
    Abstract ( 2273 )   [Full Text(HTML)] () PDF (558KB) ( 698 )  

    The periodic mesoporous ethanesilica (PME) was synthesized in acidic medium by the condensation of 1,2-bis(trimethoxysily) ethane (BTME) using triblock copolymer EO20PO70EO20 (P123) as template, cetyltrimethylammonium bromide (CTAB) as co-surfactant and ethanol as co-solvent. The results of nitrogen-sorption measurement, powder X-ray diffraction (XRD), and scanning electron microscopy (SEM) show that the PME has high surface area (1152 m2/g), narrow pore-size distribution, ordered pore structure, and spherical morphology. The spherical PME without further chemical modification was used as the stationary phase in reversed-phase high performance liquid chromatography. Highly efficient and rapid separation of the mixture of polycyclic aromatic hydrocarbons (benzene, naphthalene, biphenyl, phenanthrene and pyrene) was obtained on the column packed with the PME.

    Purification and Identification of Genistein in Ginkgo biloba Leaf Extract

    WANG Fengqin, JIANG Kezhi, LI Zuguang
    2007, 25 (4):  509-513. 
    Abstract ( 2812 )   [Full Text(HTML)] () PDF (736KB) ( 905 )  

    The Ginkgo biloba leaf extract was hydrolyzed under acidic conditions and neutralized with 5% aqueous NaOH. The hydrolysate was extracted with a mixture of ethyl acetate and tetrahydrofuran (7∶3, v/v), and was concentrated by the vacuum evaporation of organic solvent. Genistein was isolated from the hydrolysate using silica gel column chromatography with a gradient elution of dichloromethane and acetic ether and further recrystallized in dichloromethane. The whole process was monitored using high performance liquid chromatograph, equipped with photodiode array detector and electrospray ionization mass spectrometer/mass spectrometer (HPLC-PDA-ESI-MS/MS). The HPLC chromatogram with UV at 260 nm showed that the purity of genistein was higher than 98%. The structure of genistein was identified using UV absorption curves, nuclear magnetic resonance (1H NMR, 13C NMR) spectra, ESI-MS in negative mode and tandem MS spectra. The fragmentation mechanism for genistein was also discussed in detail: collision induced dissociation (CID) of the [M-H]- ion (m/z 269) showed that the quasi-molecular ions [M-H]- were prone to process rearrangement in the skeleton and lose neutrals, such as C3O2, CO2, CO. The Retro-Diels-Alder fragmentation was another characteristic decomposition of the ions.

    Refolding and Purification of Recombinant Human Granulocyte
    Colony-Stimulating Factor from Escherichia coli by
    Using Protein Folding Liquid Chromatography

    WANG Chaozhan, WANG Lili, GENG Xindu
    2007, 25 (4):  514-517. 
    Abstract ( 2817 )   [Full Text(HTML)] () PDF (1468KB) ( 788 )  

    Recombinant human granulocyte colony-stimulating factor (rhG-CSF) in the form of inclusion bodies expressed in Escherichia coli (E. coli) was simultaneously refolded and purified using protein folding liquid chromatography (PFLC). Cu2+-iminodiacetic acid (IDA) Sepharose was selected as the stationary phase for immobilized metal ion affinity chromatography. rhG-CSF was purified and the aggregates were diminished under a linear gradient elution of imidazole in the presence of a suitable concentration of urea. Using only one PFLC run, the refolded rhG-CSF had a specific bioactivity of 1.8 × 108 IU/mg and a purity of 97%, with the mass recovery of 32%.

    Quality Assessment on High Performance Liquid Chromatographic
    Fingerprints of Ginkgo Leaf Extract and Dipyridamole
    Injection by Double Qualitative Similarities and
    Double Quantitative Similarities

    SUN Guoxiang, REN Peipei, BI Yumeng, BI Kaishun, SUN Yuqing
    2007, 25 (4):  518-523. 
    Abstract ( 2072 )   [Full Text(HTML)] () PDF (481KB) ( 1078 )  

    A novel method of double qualitative similarities and double quantitative similarities was established for the evaluation of chromatographic fingerprints and it has been applied on the quality assessment of the high performance liquid chromatographic (HPLC) fingerprint of ginkgo leaf extract and dipyridamole injection. The chromatographic fingerprints containing 41 co-possessing peaks were obtained by choosing rutin peak as the referential peak. The chromatographic fingerprints were evaluated by the double qualitative similarity parameters (S and S′) and the double quantitative similarity parameters (C and P). A variety of characteristics were investigated when big peaks and small peaks were missing. S can clearly reflect the distribution of chemical constituents, and C can reflect the total content of the co-possessing peaks of the sample, but both of them were significantly influenced by the big peaks and not by the missing of small peaks. S′ and P are of equally weighing to all fingerprint peaks, and they can reflect sensitively the missing of small peaks . The double qualitative similarities (S and S′) and the double quantitative similarities (C and P) can be combined to provide accurate qualitative and quantitative assessments for the quality of traditional Chinese medicine with regarding to the changes or lacks of both big peaks and small peaks. Meanwhile, the concepts of direction cosine and decomposition value of similarity were firstly put forward to describe the characteristics of chromatographic fingerprints, by which the contribution of each common peak to total similarity and the change of similarity under the missing of different peaks were quantified. The HPLC fingerprints can be used in the quality control of ginkgo leaf extract and dipyridamole injection.

    Isolation and Identification of the Mixture of L-Hydroxyproline
    Oligo-Peptides by Reversed-Phase High Performance
    Liquid Chromatography and Electrospray
    Ionization Tandem Mass Spectrometry

    SUN Yanting, LU Kui, MA Li, CAO Shuxia, ZHAO Yufen,
    2007, 25 (4):  524-527. 
    Abstract ( 2050 )   [Full Text(HTML)] () PDF (451KB) ( 730 )  

    A reversed-phase high performance liquid chromatographic-electrospray ionization tandem mass spectrometric method (RP-HPLC/MS2) was developed for the analysis and identification of a reaction mixture of L-hydroxyproline oligo-peptides. The mixture was separated on a YWG C8 column (10 μm, 250 mm×10 mm) using acetonitrile-water containing 0.06% trifluoroacetic acid (2∶98, v/v) as the mobile phase. The separation conditions were optimized. The mixture was analysed with electrospray ionization mass spectrometry (ESI-MS) and ESI-MS/MS in positive mode. MS and MS2 spectra of individual chromatographic peak were obtained. It indicated that there were hydroxyproline dipeptide, hydroxyproline tripeptide and hydroxyproline cyclo-dipeptide in the mixtures, besides hydroxyproline. The described method can be effectively applied to perform identification of hydroxyproline oligo-peptide mixtures.

    Isolation and Purification of Solanesol from Potato Leaves
    by High-Speed Counter-Current Chromatography and
    Identification by Atmospheric Pressure Chemical
    Ionization Mass Spectrometry

    HU Jiangyong, LIANG Yong, XIE Ya, HUANG Zhaofeng, ZHONG Hanzuo
    2007, 25 (4):  528-531. 
    Abstract ( 2490 )   [Full Text(HTML)] () PDF (313KB) ( 751 )  

    Preparative high-speed counter-current chromatography (HSCCC) was used for the isolation and purification of solanesol from potato leaves. Experimental conditions of the extraction of solanesol from potato leaves have been optimized. An ultrafine extraction method was applied in this study. The efficiency using an ultrafine extraction was found to be improved in the investigation, the yields of solanesol by different extraction methods were 0.083% by ultrafine extraction and 0.050% by ultrasonic extraction. Using n-hexane-methanol (10∶7, v/v) as the two-phase solvent system, preparative HSCCC was successfully performed with the yield of 5 mg solanesol at 98.7% of purity from 60 mg of crude extract in the one-step separation. The mobile phase was the lower phase and operated at a flow rate of 1.5 mL/min, while the apparatus rotated at 800 r/min. The solanesol was identified by the atmospheric pressure chemical ionization mass spectrometry (APCI-MS). The ionization and cleavage mechanisms of solanesol in APCI-MS and APCI-MS/MS are discussed.

    Determination of Isomerized α-Acids in Beer Using Solid Phase
    Extraction-High Performance Liquid Chromatography

    LI Qi, ZHOU Tian, GU Guoxian
    2007, 25 (4):  532-535. 
    Abstract ( 1845 )   [Full Text(HTML)] () PDF (288KB) ( 711 )  

    An analytical method for four isomerized α-acids in beer was developed using solid phase extraction (SPE) coupled with high performance liquid chromatography (HPLC). The method for solid phase extraction was systematically optimized. The optimal conditions were determined as follows: 2 mL of acidic methanol as eluting solvent through a Sep-Pak C18 cartridge and the pH value of beer was adjusted to 2.5. Under these conditions, the recoveries of four isomerized α-acids for spiked standards (n=10) were 90.6%-96.4% and the relative standard deviations (RSDs) were generally less than 4%. The detection limits for iso-α-acid, rho-iso-α-acid, tetrahydro-iso-α-acid and hexahydro-iso-α-acid were 0.14 mg/L, 0.36 mg/L, 0.33 mg/L and 0.53 mg/L, respectively. The method is sensitive, accurate and suitable for the analysis of isomerized α-acids in beer.

    Simultaneous Determination of Sulfonylurea and Diphenylether
    Herbicide Residues in Soybean and Rice by High
    Performance Liquid Chromatography

    WANG Hexing, LI Yuanqian, YONG Li, GU Suying, YANG Xiaoqi, LI Lei
    2007, 25 (4):  536-540. 
    Abstract ( 2308 )   [Full Text(HTML)] () PDF (310KB) ( 877 )  

    A high performance liquid chromatographic (HPLC) method for the simultaneous determination of sulfonylurea herbicide and diphenylether herbicide residues in soybean and rice samples was developed and evaluated. The analytes in soybean and rice samples were extracted with acetonitrile. The extract was cleaned up using an SPE-C18 cartridge, separated and quantitatively determined by reversed-phase HPLC with an ultraviolet detector. The conditions of the pretreatment for soybean and rice samples as well as the parameters of chromatographic separation were optimized. The method had a good linearity in the range of 0.05-2.0 mg/L. The quantitative limits (LOQ) of the 8 herbicide residues were 0.01-0.02 mg/kg. The spiked recoveries were in the range of 91.6%-116.1% for soybean samples and 76.6%-110.8% for rice samples with the relative standard deviations of 1.0%-12.2%. It is concluded that the proposed method is rapid, accurate and sensitive and can be used for the determination of the eight herbicide residues in soybean and rice.

    Simultaneous Determination of 15 Hormones in Cosmetics Using Ultra Performance Liquid Chromatography

    MA Qiang, WANG Chao, WANG Xing, BAI Hua, CHEN Wei, WU Ting, ZHOU Xin, YU Wenlian
    2007, 25 (4):  541-545. 
    Abstract ( 2193 )   [Full Text(HTML)] () PDF (231KB) ( 1354 )  

    An analytical method based on ultra performance liquid chromatography has been developed for the simultaneous determination of 15 hormones (triamcinolone, hydrocortisone, prednisone, cortisone, 6α-methylprednisolone, betamethasone, dexamethasone, prednisolone acetate, hydrocortisone acetate, estriol, β-estradiol, estrone, diethylstilbestrol, testosterone and progesterone) in cosmetics. Various cosmetic samples were extracted with methanol under ultrasonication, and then cleaned up by a Oasis HLB solid phase extraction cartridge. The 15 hormones were separated and detected within 6 min on a Waters ACQUITY UPLC BEH C18 column (1.7 μm, 2.1 mm×50 mm) by gradient elution with acetonitrile and water system. In the range of 1-25 ng, the calibration curves of 15 hormones showed good linearity with the correlation coefficients larger than 0.9995. The mean recoveries at the three spiked levels (2, 10, 20 mg/kg) were 88.2%-102.4%with the relative standard deviations of 1.6%-7.4%.

    Simultaneous Analysis of Multiple Classes of Antibiotics in Urban
    River Water by High Performance Liquid Chromatography

    TAN Jianhua, TANG Caiming, YU Yiyi, PENG Xianzhi
    2007, 25 (4):  546-549. 
    Abstract ( 1982 )   [Full Text(HTML)] () PDF (245KB) ( 1080 )  

    A simple and reliable method was developed for simultaneous determination of multi-class antibiotic residues in aquatic environment, including three fluoroquinolones (ofloxacin, norfloxacin, ciprofloxacin), three sulfonamides (sulfadiazine, sulfamethoxazole, sulfamethazine), chloramphenicol and trimethoprim. Samples were extracted and concentrated through hydrophilic-lipophilic balance (HLB) cartridges. Selected antibiotic compounds were determined by high performance liquid chromatography (HPLC) using internal standard quantification method. Antibiotics were separated on an Agilent XRD C18 column (150 mm×3.0 mm, 3.5 μm) with a gradient elution using acetonitrile and 0.1% (v/v) formic acid in purified water at a flow rate of 0.25 mL/min and the column temperature of 25 ℃. Fluoroquinolones were quantified by fluorescence detection (FLD) and the others by ultraviolet detection at 280 nm. The recoveries for the antibiotics are ranging from 80% to 120% for spiked tap water, and 63% to 106% for urban river water samples, respectively, with relative standard deviation lower than 18%. The limits of quantification were 0.030-0.080 μg/L for surface waters. The method has been successfully applied to monitor the occurrence of antibiotic residues in the urban river waters from the Pearl River in Guangzhou. Sulfamethoxazole, ofloxacin, norfloxacin and ciprofloxacin were detected at mass concentrations ranging from 0.197 to 0.510 μg/L.

    Simultaneous Determination of Vindoline, Catharanthine and
    Anhydrovinblastine in Catharanthus roseus by High
    Performance Liquid Chromatography

    YANG Lei, TANG Zhonghua, ZU Yuangang
    2007, 25 (4):  550-552. 
    Abstract ( 1838 )   [Full Text(HTML)] () PDF (177KB) ( 780 )  

    A high performance liquid chromatographic (HPLC) method with gradient elution was developed for the simultaneous determination of vindoline, catharanthine and anhydrovinblastine in Catharanthus roseus. The analytes were separated on a Waters 5C18-MS-Ⅱcolumn (4.6 mm×250 mm) and detected at 220 nm. The mobile phases were methanol-1%(v/v) diethylamine solution (adjusted to pH 7.3 with phosphate) for gradient elution at temperature of 25 ℃. The calibration curves for vindoline, catharanthine and anhydrovinblastine showed good linearity in the ranges of 0.03-1 mg/mL (r=0.9997), 0.03-1 mg/mL (r=0.9999) and 0.01-0.5 mg/mL (r=0.9986), respectively. The recoveries were 96.8%, 97.0%, and 96.4% and the relative standard deviations (RSDs) were 1.53%, 1.37%, and 1.96%. The method is accurate, rapid and simple for the determination of vindoline, catharanthine and anhydrovinblastine in Catharanthus roseus.

    Simultaneous Determination of Residues of Three Fluoro-
    quinolones in Chicken Using High Performance Liquid
    Chromatography with Post-Column Derivatization
    and Terbium Sensitized Fluorescence

    QI Kezong, ZHU Liangqiang, SUN Guoren, SHI Zuhao, PENG Kaisong
    2007, 25 (4):  553-556. 
    Abstract ( 2120 )   [Full Text(HTML)] () PDF (270KB) ( 588 )  

    A method of high performance liquid chromatography with post-column derivatization and terbium sensitized fluorescence for simultaneous determination of residues of ciprofloxacin, norfloxacin and enrofloxacin in chicken was established, based on the effect that Tb3+ can sensibilize fluorescence of fluoroquinolones. Under the optimal chromatographic condition, three fluoroquinolones were separated on a C18 column with 0.05 mol/L acetic acid/acetate buffer-acetonitrile (89∶11, v/v) as the mobile phase, and at a flow rate of 0.8 mL/min; then were derivatized with 8×10-5 mol/L Tb3+ at 40 ℃, and at a flow rate of 0.5 mL/min; finally were detected using a fluorescence detector (λex=271 nm, λem=545 nm). The recoveries of three fluoroquinolones ranged from 66.3%-88.0% at the added levels of 1.0, 10.0, 50.0, and 100.0 ng/g, and the relative standard deviations (RSDs) were less than 15.0%. The linear range for quantitative analysis was between 0.1 and 500 ng/mL. All the RSDs of the inter-day and intra-day analyses were less than 13.0%. The detection limits were 0.05 ng/g for ciprofloxacin and norfloxacin and 0.08 ng/g for enrofloxacin. The method is sensitive for the determination of multi-residues of fluoroquinolones in chicken.

    Comparison of the Determination Results of Gentamycin
    C Components by High Performance Liquid
    Chromatography with Different Detectors

    LI Wei, HU Changqin, WANG Mingjuan
    2007, 25 (4):  557-561. 
    Abstract ( 2593 )   [Full Text(HTML)] () PDF (412KB) ( 867 )  

    The results were compared for determining gentamycin C components by high performance liquid chromatography with different detectors in pharmacopoeias. Evaporative light-scattering detector (ELSD) was first used in Pharmacopoeia of People’s Republic of China (ChP) 2005, while British Pharmacopoeia (BP) 2005 adopted pulsed amperometric detector in quantitative analysis of gentamycin. As gentamycin C components could not produce signals using UV detector, pre-column derivatization method made the detection possible, referring to United State Pharmacopoeia (USP) 29th Ed, etc. However, the absorbance of by-products and reagents overlapped with gentamycin C components, which caused much trouble in integrating peaks. That is the reason that the quantitative results were calculated based on area and height in different editions of ChP. To make the determination more accurate, “pure” chromatogram was resolved by heuristic evolving latent projection (HELP) method, based on calculating the data obtained with high performance liquid chromatography-diode array detection (HPLC-DAD) using pre-column derivatization with o-phthalic aldehyde (OPA). After subtracting the interference of impurities, gentamycin C1 component in samples was quantitatively determined accurately. The results were comparable to what achieved with HPLC-evaporative light-scattering detector and column switching. At the same time, it was proved that the HPLC-ELSD method in ChP 2005 was more reliable than the pre-column derivatization method.

    Determination of Phenol and Formaldehyde in Resol Resins
    by High Performance Liquid Chromatography

    LIU Xiuling, ZHANG Wuwei, SUI Guohong, NING Qiang
    2007, 25 (4):  562-564. 
    Abstract ( 2268 )   [Full Text(HTML)] () PDF (138KB) ( 1018 )  

    A high performance liquid chromatographic (HPLC) method was developed for the separation of formaldehyde and phenol from the other components of resol resins. The sample was dissolved in methanol and treated with 2,4-dinitrophenylhydrazine in order that formaldehyde was derivatized to form 2,4-dinitrophenylhydrazone with high UV absorbance. The separation was carried out on a Waters Symmetry C18 column (5 μm,4.6 mm × 250 mm) with methanol-water (43∶57, v/v) as the mobile phase at a flow rate of 0.8 mL/min. The detection wavelength was 270 nm for phenol and 360 nm for the derivative of formaldehyde. The results showed that derivatization had no effect on the determination of phenol. The relative standard deviations (RSDs) of the contents of phenol and formaldehyde were below 5%, the limits of detection (LODs) were below 1 μg/L, and the recoveries were between 96% and 105%. With this method, formaldehyde and phenol in the resol resins can be determined by only one injection. As a result, this method would meet effective control for quality of this kind of resol resins.

    Analysis of Polyphenols in Tobacco Using Reversed-Phase
    High Performance Liquid Chromatography

    LI Fujuan, CAI Wensheng, SHAO Xueguang
    2007, 25 (4):  565-568. 
    Abstract ( 2151 )   [Full Text(HTML)] () PDF (350KB) ( 917 )  

    A reversed-phase high performance liquid chromatographic (RP-HPLC) method for the determination of 9 polyphenols in plant was developed. The separation conditions of the chromatography were optimized with a Sunfire-C18 (0.5 μm, 4.6 mm×150 mm) separation column. The relationship of acetic acid concentration in mobile phase and the retention time, the effect of mobile phase composition and the ratio of acetic acid solution and methanol on retention time were studied separately, and a gradient elution was established. Quantitative results showed that the limits of detection were 13.26-59.29 mg/kg for the 9 analytes in plant. The linear range for the quantification of the 9 analytes was 3.0-100.0 mg/L and the correlation coefficients (r2) were between 0.9979-0.9999. Tobacco sample was extracted by ultrasonication using 80% methanol, and determined using HPLC. The spiked recoveries from tobacco samples were 96.8%-108%, and their relative standard deviations were less than 3.8% (n=3). Chlorogenic acid and rutin in real tobacco samples were also determined.

    Determination of Alachlor Residue in Agricultural Products

    WANG Mingtai, MOU Jun, ZHOU Xiao, SONG Liguo, HAN Dachuan
    2007, 25 (4):  569-572. 
    Abstract ( 2040 )   [Full Text(HTML)] () PDF (416KB) ( 690 )  

    A method of the determination of alachlor residue in agricultural products was developed. Four different kinds of objects, corn, peanut, spinach, and orange were selected as representatives of main agricultural products. The sample was extracted with acetone-water (8∶2, v/v). The extract was partitioned with dichloromethane, cleaned up by gel permeation chromatography (GPC) and solid phase extraction (SPE) in order to completely separate colorants from alachlor in the sample. The eluate was evaporated under vacuum to nearly dry and diluted with acetone to a definite volume. The solution was determined and identified by gas chromatography-mass spectrometry (GC-MS) using external standard method. The recoveries were 86.0%-98.2%, and relative standard deviations were 5.1%-6.7%with spiked at 0.010-0.200 mg/kg of alachlor in blank samples. The limit of quantification of this method was 0.010 mg/kg.

    Rapid and Simultaneous Determination of Thirteen Organic Phosphorous Pesticide Residues in Spinach Using Gas Chromatography-Mass Spectrometry Coupled with Stomach Large Volume Injection and
    Mini Solid Phase Extraction

    LI Li, XU Xiuli, DING Gangdou, LI Xiang, ZHANG Yao, SUN Yizhi,HE Yujian, ZHONG Weike, CHEN Yanzhang, WANG Daning
    2007, 25 (4):  573-576. 
    Abstract ( 2205 )   [Full Text(HTML)] () PDF (226KB) ( 821 )  

    A stomach large volume injection-gas chromatography-mass spectrometry (LVI-GC-MS) coupled with mini solid phase extraction (SPE) method for the rapid and simultaneous determination of 13 organic phosphorous pesticide residues in spinach samples is presented. The compounds were identified with their retention times and the abundance ratios of qualifier and target ions. Quantification was calculated based on the extraction of spiking standards in a blank sample. The limit of detection (LOD) was determined by the experimental value of the signal-to-noise ratio of 3∶1, and the limit of quantification (LOQ) was defined at the experimental value of the signal-to-noise ratio of 10∶1. The recoveries obtained ranged from 76.8% to 114.0% with the relative standard deviations between 1.5% and 17.6% except dimethoate. The LODs ranged from 0.5 to 25 μg/kg. This simple, rapid and reliable method has wide applications for the simultaneous determination of multiple pesticide residues in spinach and possibly other species.

    Matrix Solid-Phase Dispersion and Gas Chromatography/Mass
    Spectrometry for the Determination of Phthalic
    Acid Esters in Vegetables

    WANG Minglin, KOU Lijuan, ZHANG Yuqian, SHI Yanxi
    2007, 25 (4):  577-580. 
    Abstract ( 2460 )   [Full Text(HTML)] () PDF (491KB) ( 988 )  

    A method based on matrix solid-phase dispersion (MSPD) and gas chromatography/mass spectrometry (GC/MS) to determine dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), butylbenzyl phthalate (BBP) and di-2-ethylhexyl phthalate (DEHP) in vegetables was developed. The method, which required Florisil as solid dispersion sorbent, graphitized carbon black as purificant and ethyl acetate as eluting solvent, is simple, fast and suitable for the preparation of a large number of samples. The results showed that linearity of response over the five phthalic acid esters was good from 0.05 to 10.00 mg/kg. The recoveries of spiked samples ranging from 76% to 90% and the relative standard deviations ranging from 2% to 7% were obtained. The limits of detection for the method were from 0.01 to 0.024 mg/kg.

    Determination of 36 Pesticide Residues in Mushroom by Gel
    Permeation Chromatography and Gas Chromatography-
    Tandem Mass Spectrometry
    YU Shengliang, YANG Guipeng, FU Meng
    2007, 25 (4):  581-585. 
    Abstract ( 2233 )   [Full Text(HTML)] () PDF (177KB) ( 1131 )  

    A gel permeation chromatographic method was developed for the extraction of 36 pesticides from mushroom prior to gas chromatography with a triple quadrupole mass spectrometric determination. The extraction was based on homogenization with ethyl acetate using a high speed homogenizer. A gel permeation chromatographic clean-up process with ethyl acetate-cyclohexane (1∶1, v/v) as mobile phase was applied to the extracts to separate the low-molecular mass pesticides from the high molecular mass compounds in the mushroom. The 7-15 min eluate fraction was collected for subsequent analysis. The target compounds were quantified in the final extract by gas chromatography using a triple quadrupole mass spectrometer with multiple reaction monitoring (MRM). In the linear range (0.01-1.0 mg/L) of each pesticide, the correlation coefficient was higher than 0.99.The average recoveries (spiked at the levels of 0.01, 0.05, 0.10 mg/kg) were from 72.6% to 117.1% with the relative standard deviations from 2.0% to 10.8%(n=5). The limits of detection (LOD) for these pesticides were from0.1 to 0.7 μg/kg and the limits of quantification (LOQ) were from 0.2 to 2 μg/kg.

    Analysis of Flavor Compositions of Chinese Distillate Spirits by Fast Gas Chromatography

    ZHANG Chao, HU Keping, HASHI Yuki, CAO Lei, WU Jie
    2007, 25 (4):  586-589. 
    Abstract ( 2053 )   [Full Text(HTML)] () PDF (397KB) ( 869 )  

    Many kinds of flavor compositions exist in Chinese traditional distillate spirits (liquor), including alcohols, aldehydes, organic acids and esters, the ratios of which decide the flavor and quality of the liquor. In general, these components can be analyzed qualitatively and quantitatively by gas chromatography. However, the traditional analytical method takes longer analysis time. To shorten the analysis time, a fast gas chromatographic method was developed for analyzing the flavor compositions in Chinese liquors. Good results were obtained using a 20 m×0.1 mm×0.1 μm fused-silica capillary column with analysis time within 12 minutes. Moreover, the reproducibility of this method was also very good, and the relative standard deviations (RSDs) of most components were less than 5% except the acids because of their higher boiling points.

    Determination of Methamphetamine in Human Blood
    Using Microwave Extraction-Gas Chromatography

    SUN Hongfeng, GU Xuexin, WANG Jifen, NI Weigui, LI Wenjun, LI Ying
    2007, 25 (4):  590-593. 
    Abstract ( 2063 )   [Full Text(HTML)] () PDF (283KB) ( 886 )  

    A method was developed for the determination of methamphetamine (MAM) in human blood using microwave extraction-gas chromatography (GC). To improve the extraction efficiency, experimental parameters on the extraction, including such as extraction solvent and its amount, pH value of blood sample, extraction time and temperature were investigated. Comparing with conventional liquid-liquid extraction method, the microwave extraction showed better efficiency under the optimal conditions. The optimal conditions were as follows: the pH of blood sample at 13, ethyl acetate as extraction solvent, extraction at 30 ℃ for 8 min. The average recovery of MAM with this extraction method was 81.4%, and the relative standard deviation was 6.4%. The limit of detection was 220 μg/L for MAM in the blood. Using this method, MAM need not be derivatized and can be separated from the matrix. The results indicate that the developed method is rapid, accurate and sensitive, and can be used for the determination of MAM in blood samples.

    技术应用

    Separation of Short-Chain Fatty Acids on a Gas Chromatographic
    Column Coated with Oxidized Lubricating Oil

    MOUSTAFA Nagy Emam
    2007, 25 (4):  606-608. 
    Abstract ( 1793 )   [Full Text(HTML)] () PDF (268KB) ( 509 )  

    The oxidized lubricating naphthenic base oil was used as a stationary phase for the separation of short-chain free fatty acids (SFFA) either as a pure sample or an aqueous solution containing 0.9-1.2 mg/L of each acid. It is found that the oil oxidation for 20 h improved the separation of SFFA in these two sample forms. This separation improvement represents not only the increase in retention volume intervals and peak symmetries in case of the pure sample but also in acid peak areas in case of the aqueous solution sample.