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Chinese Journal of Chromatography
2005, Vol. 23, No. 1
Online: 30 January 2005

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研究报告

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Molecular Topological Study on Gas Chromatographic Retention Indices of Alkane Series NIE Changming, DAI Yimin, WEN Songnian, LI Zhonghai 2005, 23 (1):  1-6.  Abstract ( 2571 )   [Full Text(HTML)] () PDF (230KB) ( 724 )   The gas chromatographic retention indices can be used to qualify some organic compounds. A new topological index based on distance matrix and branch vertex of the atoms in a molecule is proposed by defining equilibrium electronegativity of atoms in the molecule and coloring atoms in the molecular graph with equilibrium electronegativity, which appears unique to the molecular structures and has excellent structural selectivity. The multivariate linear equations of gas chromatographic retention indices are as follows: I(Squalane)=23.97842N1-3.86562N2+0.787379N3+42.33061, R=0.9922, n=70, S=13.70405, F=1396.601; I(SE-30)=23.83937N1-3.5687N2+0.939876N3+22.11952, R=0.9919, n=37, S=11.96088, F=668.8781; where the N1, N2 and N3 are a group of topological indices; n, R, S and F are sample number, regression coefficient, residual standard deviation and F-statistic value, respectively. The calculated results by the formulae indicate that the average relative deviations between calculated values and experimental data of gas chromatographic retention indices of alkane series on both squalane(column temperature 50 ℃) and SE-30 (column temperature 80 ℃) were all 1.31% and the errors were within experimental deviations. The equations can express well the change rule of the relative gas chromatographic retention indices of alkane series.

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Study of the Influence of Synthesis Conditions on the Morphology and Binding Property of (-)-Ephedrine Imprinted Polymers DONG Xiangchao, WANG Wei, WANG Haibo, SUN Hui, LI Yan, WANG Ning, LIU Shuxia 2005, 23 (1):  7-11.  Abstract ( 2458 )   [Full Text(HTML)] () PDF (461KB) ( 1773 )   Contribution of the synthesis parameters to the properties of the polymer is one of the major interests in the study of molecular imprinting technology. To have a better understanding of the influence of polymerization conditions on the polymer morphology and binding property, (-)-ephedrine imprinted polymers synthesized with different cross-linkers (ethylene glycol dimethacrylate (EDMA) and pentaerythritol triacrylate (PETRA)), porogens (chloroform and acetonitrile) and monomer concentrations were compared. The resulting polymers were characterized with their pore structure, texture and binding affinities by BET and equilibrium adsorption method. The selectivity of the polymer was evaluated with chromatographic analysis. The results suggested that CHCl3 is a good solvent for methacrylic acid (MAA)-EDMA and MAA-PETRA polymer chains which resulted in smaller polymer surface area. Quantitative determinations of the carboxyl groups in the polymer indicated that polymers synthesized with the same pre-polymerization composition except porogen can have different concentrations of functional monomer in their structures. The study showed that porogen in the molecular imprinting synthesis can affect the morphology and composition of the polymers, which influence the binding affinity of the polymers.

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Separation of Proteins in Aqueous Two-Phase Systems with High-Speed Counter-Current Chromatography ZHI Wenbo, DENG Qiuyun, SONG Jiangnan, GU Ming, OUYANG Fan 2005, 23 (1):  12-17.  Abstract ( 2667 )   [Full Text(HTML)] () PDF (684KB) ( 765 )   High-speed counter-current chromatography (HSCCC) is a continuous liquid-liquid partition chromatography, with remarkable advantages of high separation efficiency and no adsorption or denaturation by solid phase. The retention of stationary phase and the separation of proteins in polyethylene glycol 1000 (PEG1000)-phosphate aqueous two-phase system (ATPs) were studied with a multi-column high speed-counter-current chromatograph. The flow direction and speed of the mobile phase, and the rotation direction and speed of the apparatus showed different effects on the retention of the stationary phase, which reached the maximum at 33.3% with a flow rate of 0.6mL/min and a rotation speed of 900 r/min in 14.0%PEG1000-16.0%phosphate ATPs. Distinct differences in partition coefficients among cytochrome C, lysozyme and hemoglobin were found at pH 9.2 and these three proteins were successfully separated in 14.0% PEG1000-16.0% phosphate ATPs at pH 9.2 by HSCCC with the apparatus rotating at 850 r/min and the mobile phase flow rate of 1.0 mL/min. The major protein components in hen egg white, including ovaltransferrin, ovalbumin and lysozyme also show distinct differences of partition coefficients in PEG1000-phosphate ATPs at pH 9.2. Ovalbumin and lysozyme were successfully purified to homogeneity and ovaltransferrin to ca 60% purity from the hen egg white sample with yields over 90% in 15.0% PEG1000-17.0% phosphate ATPs at pH 9.2 with the apparatus rotating at 850 r/min and mobile phase flow rate of 1.0mL/min.

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Study of Capillary Electrophoresis with End-Column Electrochemical Detection for the Diuretics of ZHANG Lan, TONG Ping, HE Yu, HUANG Duanhua, CHEN Guonan 2005, 23 (1):  22-25.  Abstract ( 1967 )   [Full Text(HTML)] () PDF (215KB) ( 597 )   A method based on capillary electrophoresis with end-column electrochemical detection (HPCE-ED) was developed for the determination of the diuretics of hydrochlorothiazide (HCT) and triamterene (TAT) simultaneously. The detection electrode was a 300 μm carbon disc electrode at a working potential of +1.1 V versus Ag/AgCl electrode. The two analytes could be well separated within 8 min in a 50 cm long capillary at a separation voltage of 24 kV with a 10 mmol/L phosphate buffer (pH 7.5). Under optimum conditions, the current response was linear over about two orders of magnitude with detection limits (S/N=3) of 0.29 and 0.25 mg/L for triamterene and hydrochlorothiazide, respectively. The proposed method was successfully applied to determine the synthetic urine and real pharmaceuticals samples. The recoveries were found to be in the range of 93.5%-97.2%.

“多维色谱”专栏

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New Advances of High Performance Separation and Analytical Techniques for Proteins in Complex Biological Systems MENG Qingfang, ZHANG Yangjun, WANG Jinglan, CAI Yun, QIAN Xiaohong 2005, 23 (1):  26-31.  Abstract ( 2015 )   [Full Text(HTML)] () PDF (212KB) ( 797 )   As a new strategy, proteomics is playing more and more important roles in the life sciences after the sequencing of the human genome was completed. Because a biological system is very complex and diverse, the study and application of technological platform for the separation and analysis with high resolution, high sensitivity, high throughput and broad dynamic range have become one of the important and hot spots. The review focused on the new progress of high performance separation and analysis techniques which were applied to the field of proteomics increasingly, such as multidimensional liquid chromatography for pre-fractionation, capillary liquid chromatography coupled with mass spectrometry and capillary electrophoresis interfaced on line with mass spectrometry.

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Multidimensional Separations Used in Pharmaceutical and Biological Fields TIAN Jing, LU Xin, YANG Jun, KONG Hongwei, WANG Yuan, ZHAO Xinjie, Guowang xu 2005, 23 (1):  32-36.  Abstract ( 2299 )   [Full Text(HTML)] () PDF (179KB) ( 688 )   A review of multidimensional separations such as comprehensive two-dimensional gas chromatography (GC×GC), comprehensive two-dimensional high performance liquid chromatography (HPLC×HPLC) and their applications in pharmaceutical and biological fields is presented with 71 references. A single CO2 cryo-jet loop modulator was developed for GC×GC and it can be used to modulate compounds higher than C6 effectively. Comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC/TOF-MS) analyses of traditional Chinese medicine volatile oils such as Pogostemon cablin Benth (Cablin Patchouli), Forsythia suspensa (Thunb.) Vahl and Zedoary were reported also. As an emerging technology, multidimensional separations hold the promise and play an important role in the future pharmaceutical and biological fields.

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Dead Time Determination of the Second Dimension in a Com-prehensive Two-Dimensional Gas Chromatography KONG Hongwei, YE Fen, LU Xin, DONG Mingquan, GUO Lei, XU Guowang 2005, 23 (1):  37-40.  Abstract ( 2117 )   [Full Text(HTML)] () PDF (208KB) ( 692 )   Comprehensive two-dimensional gas chromatography (GC×GC) is rapidly gaining importance for the analysis of complex samples. In order to predict chromatogram and optimize the operational conditions, the dead time of each dimension should be obtained exactly. Two methods to calculate the dead time of the second dimension were introduced. In the first method, based on the relationship between the time differences of a series of n-alkanes substances and the apparent retention times under different pressures, the true retention time can be calculated for non-synchronous GC×GC. The retention times of homologous series were used to calculate the dead time. Another rapid method to calculate the dead time of the second dimension is based on three or more apparent retention times in a single temperature programmed chromatographic run. The results show that the dead time of the second dimension can be calculated successfully by using the proposed methods and the deviation between the two methods is less than 0.05 s.

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Nano Flow Multidimensional Liquid Chromatography for Proteome Analysis of Rat Liver WANG Yan, GAO Mingxia, GU Xue, ZHANG Xiangmin 2005, 23 (1):  41-45.  Abstract ( 2213 )   [Full Text(HTML)] () PDF (765KB) ( 696 )   A nano flow comprehensive multidimensional liquid chromatography was developed. By using this separation platform, complex samples can be injected, desalted, separated and analyzed in complete automatization. Coupling of the strong cation-exchange (SCX) with capillary reversed-phase liquid chromatography (cRPLC) is described for proteomics of rat liver. A step gradient was applied for SCX column, and a linear gradient was applied for RPLC. The flow rate through the nano scale analytical column during the separation process was maintained at 200 nL/min. The peak capacity for the nano-2D-LC was up to 620 under these conditions.

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Applications of Two-Dimensional Liquid Chromatography Coupled to Mass Spectrometry for the Separation and Identification of Compounds in Ginkgo biloba　Extracts CHEN Xueguo, KONG Liang, SHENG Lianghong, LI Xin, ZOU Hanfa 2005, 23 (1):  46-51.  Abstract ( 2270 )   [Full Text(HTML)] () PDF (1294KB) ( 797 )   A comprehensive two-dimensional liquid chromatographic separation system based on the combination of an immobilized liposome chromatographic (ILC) column and an ODS column was developed for the separation of components in Ginkgo biloba, a traditional Chinese medicine. Two columns were coupled by a two-position, eight-port valve equipped with two storage loops, and the system was controlled by a computer. The effluent was detected both by a diode array detector and by an atmospheric pressure chemical ionization (APCI) mass spectrometer. Under the optimization separation conditions with the separation system, more than 41 components in the methanol extract of Ginkgo biloba were resolved. According to their UV and mass spectra, 13 of them were preliminarily identified as ginkgolide B, ginkgolide C, bilobalide, rutin, quercetin, quercetin-3-O-β-D-glucosyl (1-2)-α-L-rhamnoside, quercetin-3-O-β-D-glucoside, isorhamnetin, kaempferol-3-O-β-D-glucosyl (1-2)-α-L-rhamnoside, isohamnetin-3-O-β-D-rutinoside, kaempferol-3-O-β-D-glucoside, kaempferol, kaempferol-3-O-β-D-rutinoside.

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Fabrication of an Etched Porous Interface and Its Application in Capillary Electrophoresis-Based LIU Hechun, ZHANG Lihua, ZHANG Weibing, ZHANG Yukui 2005, 23 (1):  52-56.  Abstract ( 2020 )   [Full Text(HTML)] () PDF (743KB) ( 717 )   An on-column, etched fused-silica porous junction interface was designed and fabricated, and an integrated two-dimensional separation platform involving on-line coupling of capillary isoelectric focusing (CIEF) with capillary electrophoresis (CE) was constructed by the interface. The primary advantages of this novel porous junction interface over previous designs are no dead volume, simplicity, ruggedness and convenience of column switching. This interface is particularly well suited for on-line coupling of CE-based multiple dimensional separation system. The feasibility and performance of the 2D CIEF-CE system constructed by such an etched porous junction were evaluated by the separation of soluble extracts of an antler. The results indicated that the total separation time was less than 1 h, and the 2D CE separation system was found to increase the resolving power and overall peak capacity over single dimension mode.

Reviews

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Determination of Carotenoids in Foods by High Performance Liquid Chromatography LU Hongmei, LIANG Yizeng 2005, 23 (1):  57-62.  Abstract ( 2290 )   [Full Text(HTML)] () PDF (259KB) ( 944 )   Recent research on the types and contents of carotenoids in food emphasis has been increasingly placed on obtaining more accurate data. The analysis of carotenoids, however, is challenging because of the diversity and the presence of cis-trans isomers, in addition to the characteristic conjugated double bond system of carotenoids causing their particular instability, especially under light, heat, oxygen and acids. The determination of carotenoids and carotenoid ester in foods using high performance liquid chromatographic methods are reviewed. In addition, the sample extraction, treatment and some methods for chromatographic separation and analysis are briefly commented on.

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Advances of the Coatings Used in Columns for Capillary Electrophoresis and in Nanochannels of Chips LIU Chunye, CHEN Jierong 2005, 23 (1):  63-68.  Abstract ( 2114 )   [Full Text(HTML)] () PDF (212KB) ( 731 )   An overview is provided on the advancement and development of coating preparation methodology and materials used in capillaries and channels in microfluidic chip. Discussion is also given on the effects of coatings in the resolutions of separation and the reproducibility of separations. Dynamic coatings and linked coatings, classified as homo-polymers, copolymers and heterocyclic compounds, are further discussed, and so are the methods for the preparation of the coatings by cross-linked reaction, sol-gel process, photomodification and chemical deposition, etc. The discussion will be useful for the optimization of capillary columns that are used in capillary electrophoresis and nanochannels of chip.

研究简报

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Study on the Chromatographic Behavior of Bases on Dodecylamine-N,N-Dimethylene-phosphonic Acid YAO Lifeng , FENG Yuqi, DA Shilu 2005, 23 (1):  69-72.  Abstract ( 1934 )   [Full Text(HTML)] () PDF (285KB) ( 577 )   A new zirconia-based stationary phase (DPZ) was prepared by modifying zirconia with dodecylamine-N,N-dimethylenephosphonic acid (DDPA). DDPA adsorbs on zirconia with only one phosphonic group, and another is free. Besides the hydrophobic interaction provided by non-polar dodecyl, DPZ also has dipolar interaction, ion-exchange and electrostatic repellent interaction provided by the free phosphonic group and amino group at different conditions. Separations of bases on this stationary phase were achieved with satisfaction due to the various retention mechanisms. The influences of methanol content, pH value, ion type and ion strength of mobile phase were studied in detail.

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High Performance Liquid Chromatographic Method Development Using Monolithic Column for the ZHAO Xinjie, ZHENG Yufang, ZHANG Pudun, KONG Hongwei, XU Guowang 2005, 23 (1):  73-75.  Abstract ( 1835 )   [Full Text(HTML)] () PDF (189KB) ( 697 )   Modified nucleosides excreted in urine have been studied as possible bio-markers for malignant tumors. Reversed-phase high performance liquid chromatography (RP-HPLC)is one of the most popular analytical tools. However, its analysis time is longer than desired. The analytical method for urinary nucleosides has been developed using a monolithic column and a linear gradient elution of 25 mmol/L KH2PO4 solution (pH 4.55) and 60% methanol in water with UV detection at 260 nm. Twelve urinary nucleosides were completely separated. The monolithic column presented similar analytical characteristics to reversed-phase column. The time of the analysis is only 23 min, in general much shorter than the methods using a packed RP-HPLC. The method developed is sensitive, reliable and suitable for clinical applications.

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Measurement of Monoamine Transmitters in the Brains of Ovariectomized Mice Using High Performance Liquid Chromatography with Fluorescence Detection and Gradient Flow Rate Elution ZHANG　Lei, LU Yingjun, DENG Tongle, ZHENG Xiaoxiang 2005, 23 (1):  76-78.  Abstract ( 2253 )   [Full Text(HTML)] () PDF (166KB) ( 720 )   A method for the determination of norepinephrine (NE), dopamine (DA) and 5-hydroxytryptamine (5-HT) in brains of ovariectomized mice was established by using high performance liquid chromatograph with a fluorescence detector, a C18 column and a gradient flow rate delivered by a single pump. The mobile phase was a mixture of 0.1 mol/L KH2PO4 and CH3OH (9/1,v/v). Detection limits of the method were determined to be lower than 10 nmol/L, absolute recoveries were above 80% and the relative standard deviations (RSDs) of intra-day were all within 3.03％．The method has the advantages of high sensitivity and of simple sample preparation. Short analysis time and better separation of samples were also obtained.

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Determination of Angiotensin Converting Enzyme Inhibitor Activity by High Performance Liquid Chromatography WU Qiongying, MA Haile, LUO Lin, WU Shouyi 2005, 23 (1):  79-81.  Abstract ( 2040 )   [Full Text(HTML)] () PDF (183KB) ( 793 )   A high performance liquid chromatographic method to determine angiotensin-converting enzyme inhibitor activity in vitro was established by using N-hippuryl-His-Leu tetrahydrate as the reaction substrate and hippuric acid as the reaction product. The chromatographic conditions were as follows: column, ZORBAX SB-C18 (4.6 mm i.d.×150 mm, 5 μm); column temperature, 25 ℃; mobile phase, acetonitrile-distilled water (25∶75, v/v, both containing 0.05% (v/v) trifluoroacetic acid and 0.1% (v/v) triethylamine); flow rate, 0.5 mL/min; detection wavelength, 228 nm. An excellent linearity over the range of 0.005-1.000 mmol/L (r＝0.9999) was observed. The detection limit was 0.50 μmol/L. The recoveries of hippuric acid ware 99.48%-105.64%, with a relative standard deviation (RSD) of 2.20%(n＝6). It is a simple, precise and reliable assay method for developing antihypertension drugs.

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Simultaneous Determination of Pseudoephedrine Hydrochloride and Dextromethorphan Hydrobromide in Composite Pseudoephedrine Hydrochloride Dry Suspension by HPLC LI Ke 2005, 23 (1):  82-84.  Abstract ( 2610 )   [Full Text(HTML)] () PDF (182KB) ( 658 )   A simple and reliable reversed-phase high performance liquid chromatographic method (HPLC) for the routine analysis of pseudoephedrine hydrochloride and dextromethorphan hydrobromide in composite pseudoephedrine hydrochloride dry suspension has been established. HPLC determination for the drug was performed in a Lichrospher C6H6 column and detected at 220 nm. Acetonitrile-H2O-H3PO4 (50∶50∶0.1, v/v, pH 2.5, containing 1 g/L sodium dodecyl sulfate) was used as the mobile phase and the flow rate was 1.2 mL/min. The method was proved to be linear in the ranges of 1.03-206 mg/L and 5-200 mg/L for dextromethorphan hydrobromide and pseudoephedrine hydrochloride, respectively. The relative standard deviations of intra-assay (n=7) and inter-assay (n=5) were 1.0% and 1.5% for pseudoephedrine hydrochloride analysis and 1.8% and 2.2% for dextromethorphan hydrobromide analysis. The recoveries of pseudoephedrine hydrochloride and dextromethorphan hydrobromide were 95.7%-98.7% and 100.0%-101.8%, respectively. The method has been successfully applied to the simultaneous determination of pseudoephedrine hydrochloride and dextromethorphan hydrobromide in composite pseudoephedrine hydrochloride dry suspension.

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Isolation and Preparation of Sesquiterpenols from the Japanese Cedar, Cryptomeria japonica D. Don by Preparative Reversed-Phase High Performance Liquid Chromatography and Its Characterization CHEN Xiaohui, ZHANG Huifen, BI Kaishun, KIM Chul-Sa, HORIIKE Michio 2005, 23 (1):  85-87.  Abstract ( 1939 )   [Full Text(HTML)] () PDF (169KB) ( 785 )   A method for the isolation of sesquiterpenols from the Japanese Cedar, Cryptomeria japonica D.Don　by preparative reversed-phase high performance liquid chromatography (RP-HPLC) was established. The preparation of the sesquiterpenols was carried out on a preparative liquid chromatograph with a YWC-Pack C18 column, and the mobile phase was isopropanol-methanol-hexane-water (50∶35∶10∶5,v/v) at a flow rate of 5.0mL/min. The two sesquiterpenols, (-)-cubebol and (+)-2,7(14),10-bisabolatrien-1-ol-4-one, were separated by liquid chromatography and identified by spectroscopic analyses (ultraviolet (UV), infrared (IR), nuclear magnetic resonance (NMR), electrospray ionization mass spectrometry (ESI-MS)). The purities of the two sesquiterpenols were 98.7% and 99.1%, respectively.

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Determination of the Contents of Resveratrols and Piceids in Wines by High Performance Liquid Chromatography with Solid Phase Extraction SHU Youqin, CHEN Min, HE Jiguo, DAI Yunqing, FENG Ligeng 2005, 23 (1):  88-91.  Abstract ( 2235 )   [Full Text(HTML)] () PDF (183KB) ( 604 )   A method has been developed for the determination of the contents of cis- and trans-resveratrols and piceids in wines by high performance liquid chromatography (HPLC) with solid phase extraction (SPE). The techniques of SPE including the activation of the SPE column, elimination of interference and elution conditions of samples were confirmed. The analytes were separated by using a Hypersil C18 column (4.6 mm i.d.×250 mm, 5 μm) and acetonitrile-water as mobile phase with linear gradient elution. A photodiode array detector monitored at the detection wavelengths of 288 nm and 306 nm for cis- and trans-isomers, respectively. The external standard calibration curves were used in quantitation. There were good linear correlations between the concentrations and peak areas of the four components with the correlation coefficients of 0.9973-0.9999. The average recoveries were 97.4%-98.6% with relative standard deviations of 2.1%-3.2%. The detection limits were 0.002-0.005 mg/L. The method of SPE-HPLC eliminated a great deal of interferences in wines effectively by optimizing extraction conditions. The four isomers were well separated and the analytical results were improved well and truly. The results for determining 15 market wines showed that as an important bioactive substance, the resveratrol content has close relationships with brewing methods, varieties of grape and producing areas. The results also showed that it is a convenient, rapid, sensitive and accurate method. It can be used to analyze resveratrols and piceids in other natural samples.

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Analysis of Chloramphenicol, Thiamphenicol and Florfenicol in Chickens by High Performance Liquid Chromatography with Electrospray Ionization Mass Spectrometry CHEN Xiaoxia, YUE Zhenfeng, JI Caini, LIANG Shizhong 2005, 23 (1):  92-95.  Abstract ( 2324 )   [Full Text(HTML)] () PDF (253KB) ( 916 )   The method for the analysis of three chloramphenicols including chloramphenicol, thiamphenicol and florfenicol in chickens was developed by high performance liquid chromatography combined with electrospray ionization mass spectrometry (HPLC-ESI-MS-MS). The mass spectrometer was operated in the negative ion mode using multiple reaction monitoring for qualitative and quantitative analysis of these compounds at the same time. Only 1 g of sample was needed, and no solid phase extraction (SPE) procedure was adopted. The advantages of the method are simple operation, less organic chemicals consumed, and shorter operation time. The limits of detection (LOD) were 0.010μg/kg, and the limits of quantitation (LOQ) were 0.100 μg/kg. The linear plots were obtained between 0.050 and 1.00 μg/L. Overall recoveries were between 69.0%and 92.8%with relative standard deviations between 6.3%and 12.9%.

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Preparative Isolation and Purification of Cinnamoyl-C-Glycoside Chromone from Aloe Vera by High- PAN Xia, CAO Xueli, DONG Yinmao, ZHAO Hua 2005, 23 (1):  96-99.  Abstract ( 2575 )   [Full Text(HTML)] () PDF (252KB) ( 737 )   Aloe chromone is a group of anti-inflammatory and anti-tyrosinase constituents found in aloe vera leaves. High-speed countercurrent chromatography (HSCCC) is reported for the preparative isolation and purification of a chromone from aloe vera. The crude extract was obtained by a series of pretreatment of aloe vera leaves and extracted from decolorizing active carbon with methanol. Then the extract was distributed between dichloromethane and water, and the organic part was then subjected to HSCCC for the isolation of chromone constituents. The chromone compounds with a high performance liquid chromatographic grade (>95%) was isolated through two step HSCCC separations by employing two solvent systems composed of chloroform-methanol-water and dichloromethane-methanol-water at volume ratios of 4/3/2 and 5/4/2, respectively. The chromone was finally identified as cinnamoyl-C-glycoside chromone by ultraviolet (UV), fast atom bombardment mass spectrometry (FAB-MS), nuclear magnetic resonance (1H NMR and 13C NMR).

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Study on Large-Volume Electrokinetic Injection of Capillary Zone Electrophoresis by Using Transient Isotachophoresis LI Yun, HE Youzhao 2005, 23 (1):  100-102.  Abstract ( 2166 )   [Full Text(HTML)] () PDF (195KB) ( 721 )   A sample pre-concentration method that combined field-amplified sample injection (FASI) induced by acetonitrile with transient isotachophoresis was applied to achieve effective concentration and the separation of cations in high-salt samples. Several important factors are discussed, such as buffer systems, terminating ions, column effective length and injection time of sample and terminating solution. A capillary column of 50 μm i.d.×65 cm (effective length of 50 cm) was employed. Solutions of 400 mmol/L LiAc-HAc (pH 4.5) and 400 mmol/L β-alanine-HAc (pH 4.5) were used as buffer solution and terminating electrolyte, respectively. The injection times of sample solution and terminating electrolyte were 270 and 90 s, respectively. Compared with conventional electrokinetic injection, the sensitivity of the proposed method was improved about 280-fold. The detection limits of propranolol and metoprolol achieved 2×10-3 and 8×10-3mg/L, respectively.

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Restriction Enzyme Pattern Analysis of Mycobacteria DNA by Capillary Electrophoresis with Laser LI Yuanqian, WANG Guoqing, MI Jianping, ZHOU Ying, ZENG Hongyan, ZHANG Chaowu 2005, 23 (1):  103-107.  Abstract ( 1928 )   [Full Text(HTML)] () PDF (743KB) ( 610 )   A new method for rapidly detecting restriction enzyme pattern of mycobacterium deoxyribonucleic acid (DNA) by capillary electrophoresis with laser induced fluorescence detection （CE-LIFD） was developed. Polymerase chain reaction was used to amplify a 439 bp fragment of 65000 (Mr) heat shock protein gene (hsp65) of mycobacterium. After digesting the amplification products by BstEⅡ and HaeⅢ respectively, the patterns of enzyme cleavaged products were detected by both CE-LIFD and agarose gel electrophoresis (AGE). The experimental parameters of CE were optimized. The restriction enzyme patterns of mycobacterium DNA can be detected under the optimum electrophoresis conditions: a coated capillary column with the length of 50 cm and 100 μm i.d., electrophoresis buffer of 45 mmol/L TBE (trihydroxymethyl aminomethane (Tris)-boric acid-ethylenediaminetetraacetic acid (EDTA)) and 11 kV running voltage. The restriction enzyme patterns for eight species of mycobacteria were studied. Relative standard deviations of the relative migration times of the DNA segments were less than 3.6%. Compared with AGE, CE is more outstanding in resolution and detection time, and it can be applied as a more effective means for DNA restriction enzyme pattern analysis.