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Chinese Journal of Chromatography
2007, Vol. 25, No. 1
Online: 30 January 2007

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Studies on Single-Cell Analysis CHENG Jieke, HUANG Weihua, WANG Zongli 2007, 25 (1):  1-10.  Abstract ( 2410 )   [Full Text(HTML)] () PDF (20452KB) ( 976 )   The single-cell analysis is a frontier field of sciences that has been developed from the interdisciplinary collaborations of analytical chemistry, biology and medicine. At the present time, the great achievements in the application of capillary electrophoresis and microfluidic chip to single-cell analysis, particularly, in the application of microfluidic chip to culture, manipulation, location, separation and detection of components of single cells, real-time detection of secretion from single-cells and high-throughput array detection have been made. The unit procedures can be made up in any device in accordance with the requirements. In this paper, the work of the author’s group is presented mainly. In addition, the developments of the capillary electrophoresis and chip electrophoresis applied to single-cell analysis in recent years are reviewed. The prospects for single-cell analysis including capillary electrophoresis and microfluidic chip, measurement and control at the cell-chip interface, and quantum dots for probing live cells are also proposed.

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Characterization of Surface Properties of 1,3,5-Triamino-2,4,6-Trinitrobenzene by Inverse Gas Chromatography NIE Fude, XU Rong, FAN Zhongyong, LI Yuesheng 2007, 25 (1):  11-15.  Abstract ( 2286 )   [Full Text(HTML)] () PDF (214KB) ( 772 )   The surface properties of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) with various particle sizes were characterized by inverse gas chromatography (IGC). The disperse component γds of surface free energy of TATB samples increased as temperature increased. The larger the particle size is, the quicker the increasing rate of the disperse component will be as the temperature increases. The γds of the coarse TATB is the highest (193.2 mJ/m2) and that of the submicron TATB is the smallest (64.0 mJ/m2) at 353 K. Due to the different preparation processes and particle sizes, the samples show obviously different Lewis acid-base properties. Fine TATB can provide positive Lewis acid-base active sites and has higher acidity. The specific components of the adsorption of polar probes on the surface of the other three types of TATB were found to be endothermic owing to the strong hydrogen bond of inter- and intra-TATB molecules. Their surface acidity and basicity constants, Ka and Kb are negative.

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Determination of Amphetamines in Human Hair Using Dynamic Liquid-Phase Microextraction and Gas Chromatography/Selected Ion Monitoring-Mass Spectrometry After Microwave erivatization ZHU Dan, MENG Pinjia, HE Hongyuan 2007, 25 (1):  16-20.  Abstract ( 2062 )   [Full Text(HTML)] () PDF (362KB) ( 1235 )   Human hair is an important specimen for drug abuse analysis owing to its easy collection, long surveillance time window and good correlation between the “degree of addiction” and actual drug concentration. A simple method for determination of 4 amphetamines in human hair was developed. The hair was digested under basic condition, and the drugs in it were extracted using microvolume of chloroform. The organic layer was then transferred into another tube to be derivatized with N-methyl-bis(trifluoroacetamide)（MBTFA） by microwave heating. Finally the reacted solution was detected by gas chromatography/selected ion monitoring-mass spectrometry (GC/SIM-MS) directly. 2-Methyl-phenyl ethylamine was used as an internal standard. Good linearities were obtained for 4 amphetamines with correlation coefficients better than 0.996. The limits of detection, based on a signal-to-noise ratio (S/N) of 3∶1, were all about 50 pg/mg for amphetamine (AM), methamphetamine (MAM), methylenedioxy-amphetamine (MDA), and methylenedioxy-methamphetamine (MDMA) in hair. The reproducibility of the method was satisfactory, with the relative standard deviations of 6.0% for AM, 13.9% for MAM, 10.2% for MDA and 9.2% for MDMA. Some real hair from the drug abusers was analyzed with this method. The minimal hair is less than 5 mg (about 20 cm). The method is highly sensitive, easy to operate, time-saving and economic, which can be used for trace analysis of amphetamines in human hair.

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Determination of Dioxins by Gas Chromatography-Mass Spectrometry Coupled with Large Volume Injection WANG Yawei, ZHANG Qinghua, JIANG Guibin, HE Qing 2007, 25 (1):  21-24.  Abstract ( 2536 )   [Full Text(HTML)] () PDF (1849KB) ( 843 )   The common analytical instrument for dioxin analysis/determination is gas chromatograph (GC) coupled with an electron capture detector (ECD), a flame ionization detector (FID), and a mass spectrometer (MS), etc. Generally, since the concentration levels in environmental samples are pg/g or pg/L, it requires a very high resolution and sensitivity for the analytical system. To solve the problem one way is to increase the amount of a sample, however, which can significantly increase the pretreatment work load. The other way is to increase the injection volume. In this paper, a method for dioxin determination was developed using GC-MS coupled with the large volume injection （LVI）. Under the condition of maintaining the same amount of solute, the comparison was studied for the changes of peak areas and peak widths by the injection of different volumes from 1 to 100 μL. The results showed that the peak area and peak width did not have obvious changes, and the separation performance was not affected compared with the traditional split/splitless injection. The detection limits obtained are improved by 12 orders of magnitude over those using split/splitless injections. Once the operation conditions are optimized, LVI is more flexible in handling samples of wide concentration ranges than the traditional split/splitless inlet approach.

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Determination of Pyrethroid Pesticide Residues in Tobacco Leaves and Tea Using Stir Bar Sorptive Extraction-Thermal Desorption and Gas Chromatography-Mass Spectrometry HOU Ying, CAO Qiue, XIE Xiaoguang, WANG Baoxing, XU Jicang, YANG Lei, YANG Yan, YANG Yong 2007, 25 (1):  25-29.  Abstract ( 2463 )   [Full Text(HTML)] () PDF (355KB) ( 1143 )   A novel method for the determination of 5 pyrethroid pesticide residues in tobacco leaf and tea samples was established. The pesticide residues in the samples were extracted and concentrated with stir bar, desorbed by thermal desorption system, and then determined by gas chromatography-mass spectrometry (GC-MS). The pesticide residues in the samples were extracted with a stir bar at 1100 r/min for 1 h. The desorption was carried out at 300 ℃ for 4 min under a helium flow of 50 mL/min while maintaining a cryofocusing temperature of 0 ℃ in the CIS-4 injector of the GC-MS system. Finally, the CIS-4 injector was raised to a temperature of 300 ℃ and then the analytes were separated by GC and detected by MS. The limits of detection of this method for the tobacco leaves ranged from 3.3 ng to 11.4 ng. The recoveries of pesticides from the tobacco leaves ranged from 94.8% to 103.4% and the relative standard deviations (RSDs) of peak areas ranged from 5.3% to 8.6% (n=6). The limits of detection of this method for tea ranged from 4.2 ng to 10.5 ng. The recoveries of pesticides from tea ranged from 98.2% to 110.1% and the RSDs of peak areas were less than 9.6% (n=6). Therefore, this method can satisfy the requirements for the rapid analysis of pesticide residues in the tobacco leaf and tea samples.

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Determination of Neutral Chemical Constituents in Flue-Cured Tobacco by Comprehensive Two-Dimensional Gas Chroma- tography and Time-of-Flight Mass Spectrometry LU Hongliang, ZHAO Mingyue, LIU Huimin, GONG Anda, YU Jing, ZHENG Hunan, LIANG Lili, LI Li, WEI Bujian 2007, 25 (1):  30-34.  Abstract ( 2337 )   [Full Text(HTML)] () PDF (165KB) ( 975 )   A method was established to analyze neutral chemical constituents in tobacco accurately by comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry (GC×GC-TOFMS). A DB-Petro column (50 m×200 μm×0.5 μm) was chosen as the column for the first dimension, and a DB-1701 column (2.3 m×100 μm×0.1 μm) was chosen as the column for the second dimension. The modulation period was set at 8 s, and the column pressure was 550 kPa. The initial temperatures of the two columns were set at 80 ℃ and 85 ℃ respectively and then increased with temperature programming. The contents of the neutral chemical constituents in different positions of tobacco leaves, product regions and varieties of tobacco were compared. The results showed that the total contents of the 24 neutral fractions in the middle leaves was the most, then in the upper leaves and the least in the lower leaves. These contents in the flue-cured tobacco produced by Brazil was the highest, followed by Zimbabwe, Yunyan85, Zhongyan101, NC89 and K326. In four kinds of tobacco, the total contents of the 24 neutral fractions in Oriental tobacco was the highest, followed by Burly tobacco, Flue-cured tobacco and Maryland tobacco.

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Application of Single Drop Microextraction in the Determination of Phthalate Esters in Food by Gas Chromatography-Mass Spectrometry LI Meigui, LI Yuanxing, MAO Liqiu 2007, 25 (1):  35-38.  Abstract ( 2807 )   [Full Text(HTML)] () PDF (1250KB) ( 953 )   A novel, simple, fast and environment-friendly method based on single drop microextraction (SDME) was developed for the determination of phthalate esters in food by gas chromatography-mass spectrometry (GC-MS). The effects of the nature of organic solvents, microdrop volume, the depth of microdrop in sample solution, extration time and stirring rate on the extraction efficiency were investigated separately. The optimal SDME conditions, 2.0 μL of toluene, 0.75 cm of the depth of microdrop, 1000 r/min of stirring rate and 20 min of extraction time, were obtained and used for the analysis of dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), dioctyl phthalate (DOP) and diethylhexyl phthalate (DEHP) in food. At first, a sample was dissolved with de-ionized water and then extracted with ultrasonication for 15 min. Then, it was filtrated and the solution was extracted and concentrated by a single drop of a solvent. Finally, it was analyzed by GC-MS. The reproducibility, linearity, recovery, and limit of detection of the method were studied. The results showed that the limits of detection (LOD) were between 25 ng/L and 0.8 mg/L. The overall recoveries were 87.1%114.4% with the relative standard deviations of 4.9%11.6%. This method has been successfully applied to the analysis of food samples.

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Determination of Isopropylthioxanthone Residue in Milk Migrated from Packaging Materials by Gas Chromatography-Mass Spectrometry DENG Xiaojun, GUO Dehua, LI Bo, ZHU Jian, YIN Ping 2007, 25 (1):  39-42.  Abstract ( 2072 )   [Full Text(HTML)] () PDF (406KB) ( 821 )   Isopropylthioxanthone (ITX) has been widely used as the photoinitiator in printing ink of packaging materials in modern food packaging industry. A method regarding the identification and qualification of ITX residue in milk migrated from food contact packaging materials was developed. The procedure was based on the gas chromatography-mass spectrometry (GC-MS) for screening and gas chromatography-tandem mass spectrometry (GC-MS/MS) for confirmation after a solid phase extraction (SPE) step using Florisil column with anthracene D10 (AD10) as the internal standard. Data was acquired in selective ion monitoring (SIM) mode with the following ions: m/z 184,m/z 224, m/z 239, m/z 254 for ITX and m/z 80, m/z 94, m/z 188, m/z 160 for AD10 in screening method of GC-MS. The m/z 254 was selected as the parent ion and m/z 239 as the daughter ion in the conformation method of GC-MS/MS. Data acquired employed the transition of m/z 254, m/z 239 for ITX and m/z 188, m/z 160 for AD10. The method gave limits of quantification (LOQ) of 7.0 μg/L(GC-MS) and 5.0 μg/L (GC-MS/MS) respectively as well as recoveries ranged from 74.9% to 89.6%. The analysis of real samples found two positives out of 11 different milk stuffs available using this method.

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Headspace Solid-Phase Microextraction-Gas Chromatography-Mass Spectrometry for Analysis of Volatile Components from Atractlodes macrocephala Koidz. GUO Fangqiu, HUANG Lanfang, ZHOU Shaoyun 2007, 25 (1):  43-47.  Abstract ( 2698 )   [Full Text(HTML)] () PDF (389KB) ( 1245 )   Headspace solid-phase microextraction (HS-SPME) technique was employed to extract the volatile components from Chinese traditional medicine, Atractlodes macrocephala Koidz. The volatile components were isolated and identified successfully by gas chromatography-mass spectrometry(GC-MS). The results from HS-SPME-GC-MS were compared with those obtained from steam distillation-GC-MS (SD-GC-MS) with a good agreement. The volatiles were collected using a polydimethylsiloxane-divinylbenzene (PDMS-DVB) fiber by HS-SPME. The best response was obtained when the extraction temperature was 70 ℃, the equilibrium time and extraction time were all 30 min and the desorption time was 4 min. Analysis was performed by GC-MS with a polysiloxane capillary column (30 m×0.25 mm, film thickness 0.25 μm) using He as the carrier gas and a programmed temperature run. Forty-one components accounting for 90.81% were identified. The main components (relative amount more than 1%) of the samples by HS-SPME were atractylone (40.12%), γ-elemene (14.73%), aromadendrene (13.05%), eudesma-4(14),11-diene (5.46%), caryophyllene (2.56%), patchoulene (2.55%), 6,10,11,11-tetramethyl-tricyclo［6.3.0.1(2,3)］undec-7-ene (2.11%), cedrene (1.48%), α-caryophyllene (1.48%) and selina-4(14)-7(11)diene-8-one (1.01%). By SD-GC-MS, 31 components accounting for 88.19% were identified and all these components could be extracted by SPME except trans-β-ocimene which accounts only 0.10%. The results showed that the HS-SPME technique can be used to extract the the volatile components from Atractlodes macrocephala Koidz. in place of the traditional time-consuming SD.

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Determination of Trace Phenol Compounds Using Gas Chromatography-Mass Spectrometry Coupled with Tenax Adsorption Tube for Enrichment of Air Samples YANG Lili, HU Enyu, MU Yingfeng, JI Ying 2007, 25 (1):  48-52.  Abstract ( 2404 )   [Full Text(HTML)] () PDF (404KB) ( 1054 )   A novel determination method for trace of seven phenol compounds in air samples has been established. They were collected with Tenax adsorption tube (180 mm×60 mm glass tube packed with 150 mg Tenax (4060 mesh)) and desorbed with methanol. Five microlitres of naphthalene-D8 (internal standard) solution was added to the eluate. One microlitre of the mixture solution was injected into an HP-5MS capillary column (30 m×0.25 mm×0.25 μm) and determined by gas chromatography-mass spectrometry with selected ion monitoring (GC-MS/SIM). The selected ions were m/z 94, 95, 66, 108, 107, 77, 90, 122, 121, 107 and 136. The quantitative ions, m/z 94 for phenol, m/z 108 for cresol, m/z 122 for xylenol and m/z 136 for internal standard, were selected. The average recoveries of phenol compounds (spiked at the levels of 0.25, 1.00, 5.00 μg) ranged from 92.4% to 102% and the relative standard deviations were less than 4.8%. When the air sample volume was 10 L, the detection limits were less than 0.001 mg/m3. Good linearities were observed in the range from 0.05 to 20.0 mg/L. The method is simple, fast, sensitive and accurate for the determination of phenol compounds in air samples.

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Extraction and Determination of Essential Oils in Indocalamus latifolius Leaves and Indocalamus tessellatus Leaves LI Shuifang, WEN Ruizhi, ZENG Dong, LI Zhonghai 2007, 25 (1):  53-57.  Abstract ( 2347 )   [Full Text(HTML)] () PDF (348KB) ( 967 )   Indocalamus leaves are the generic name of the leaves of Indocalamus (Graminales) plants. The essential oils in Indocalamus latifolius leaves and Indocalamus tessellatus leaves were extracted by steam distillation method. Ether was used as the solvent to extract volatile compounds many times. Both the volatile compounds in Indocalamus latifolius leaves and Indocalamus tessellatus leaves were analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that thirty-seven compounds were identified for the essential oils extracted from Indocalamus latifolius leaves, and its main components were found to be 3-hexen-1-ol, (Z)-; 1-hexanol; benzyl alcohol; hexanal; furan, 2-ethyl-; 3-buten-2-one, 4-(2,6,6-trimethyl-1-cyclohexen-1-yl), (E)-; etc. Forty-nine components were identified for the essential oils extracted from Indocalamus tessellatus leaves, and its main components were found to be 3-hexen-1-ol, (Z)-; benzyl alcohol; 3-buten-2-one, 4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-, (E)-; 2-hexenal; phenylethyl alcohol, 2-methoxy-4-vinylphenol; furan, 2-ethyl-; etc. 3-Hexen-1-ol, (Z)- was the most abundant compound in the essential oils from both Indocalamus leaves. There were ketone, aldehyde, alcohol, phenol and ester in them. The contents of ketones, aldehydes, and alcohols were found higher than those of other compounds in the two essential oils.

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Purification and Identification of a Novel ACE Inhibitory Peptide Derived from the Mud Snail Bellamya purificata by RP-HPLC/MALDI-TOF MS XIA Shuhua, WANG Zhang 2007, 25 (1):  58-65.  Abstract ( 2315 )   [Full Text(HTML)] () PDF (1216KB) ( 910 )   Bellamya purificata is one of mud snails in fresh water found in China. The purification and identification of an angiotensinⅠ-converting enzyme (ACE) inhibitory peptide extracted from Bellamya purificata hydrolysate are described. The peptide was purified twice with semi-preparative reversed-phase high performance liquid chromatography (RP-HPLC) to obtain an active fraction with an inhibitory concentration 50%（ IC50） of 43.5 μmol/L. The primary structure of the purified peptide was identified by the high performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS) and the martix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) combining with the amino acid composition analysis. Finally, it was identified as a tetrapeptide and sequenced as Lys-Glu-Ile-Trp (KEIW), which has the common characters of ACE inhibitory peptide extracted from selfish muscle. The structure identification results from the two methods were also compared in this study. The results from ESI-MS included a lot of information, such as the total ion current chromatogram and ultraviolet scan spectrum. However, the exact structure could only be from the MALDI-TOF MS analysis, in which the exact MS/MS spectrum could be obtained. Furthermore, the m/z measurement precision of MALDI-TOF MS was 0.0001 and much better than that of 0.1 of ESI-MS.

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Simultaneous Determination of Residues of Malachite Green, Crystal Violet and Their Leuco Metabolites in Aquatic Products by Liquid Chromatography-Tandem Mass Spectrometry ZHU Kuanzheng, WANG Peng, LIN Yanfei, XIAO Songjian, MEI Surong 2007, 25 (1):  66-69.  Abstract ( 2309 )   [Full Text(HTML)] () PDF (6479KB) ( 1705 )   A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of the residues of malachite green (MG), eucomalachite green (LMG), crystal violet (CV) and leucocrystal violet (LCV) in aquatic products. The target analytes were extracted from homogenized samples with a mixture of acetonitrile and ammonium acetate buffer, partitioned against methylene chloride, and purified on tandem neutral alumina and PRS solid-phase extraction (SPE) cartridges. Chromatographic separation was achieved by using a ZORBAX SB-C18 column with an isocratic mobile phase consisting of ammonium acetate (0.5 mmol/L) and acetonitrile (10∶90, v/v) without on-line post-column oxidation with PbO2 which had been widely used in the previous methods. Identification and quantification were performed using multiple reaction monitoring (MRM) with one precursor ion, and two product ions for each analyte and electrospray ionization in positive mode. The limits of detection were 0.5 ng/g. The recoveries were in the range of 77.6%98.1%, and the relative standard deviations were less than 8.2%. The results showed that the method is suitable for the determination of residues of MG, LMG, CV and LCV in aquatic products.

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High Speed Separation and Quantitation of Ralstonia solana-cearum of Different Virulence Using High Performance Ion Exchange Chromatography LIN Juan, MA Cheng, LIU Shutao, WU Lingling, RAO Pingfan 2007, 25 (1):  70-74.  Abstract ( 2143 )   [Full Text(HTML)] () PDF (858KB) ( 837 )   High performance ion exchange chromatography coupled with laser light scattering instrument was employed for the rapid separation and quantitation of Ralstonia solanacearum of different virulence. The pure culture of Ralstonia solanacearum was successfully separated into three characteristic fractions. Each fraction was collected and inoculated onto 2,3,5-triphenyltetrazolium chloride (TTC) plates to identify its virulence. The shapes and colors of the colonies were imaged, and the average attenuation index (attenuation index=red spot diameter of colony/total colony diameter) of ten colonies of each fraction was carefully determined. Furthermore, each fraction was inoculated into SPA liquid media at 30 ℃ with shaking (200 r/min) for 48 h, the cells were harvested, suspended at a density of 1.2×109 cfu/mL, and applied to infect tomato tissue culture plantlets using leaf-cutting method. The infection mortality of the tomato tissue culture plantlets was recorded from 1 to 9 days after inoculation. The results showed that the virulences of each fraction were different on the basis of attenuation index and infection mortality. The virulence of peak 3 fraction was the strongest. On the contrary, the virulence of peak 1 fraction was the weakest. In addition, the linear relationships between different injection volumes (1180 μL) and their peak areas were investigated. The linearity was good within the range of the bacterial number of 9×1069×108 (r=0.99). This method can be potentially used as a novel tool for the rapid separation and quantitation of Ralstonia solanacearum of different virulences.

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Analysis of Monosaccharides and Uronic Acids in Polysaccharides by Pre-column Derivatization with p-Aminobenzoic Acid and High Performance Liquid Chromatography HAO Guitang, CHEN Shangwei, ZHU Song, YIN Hongping, DAI Jun, CAO Yuhua 2007, 25 (1):  75-79.  Abstract ( 2753 )   [Full Text(HTML)] () PDF (1619KB) ( 1344 )   An ion-pair reversed-phase high performance liquid chromatographic (RP-HPLC) method for the simultaneous determination of carbohydrate and uronic acids was developed. p-Aminobenzoic acid (p-AMBA) was used for pre-column derivatization of the analytes, enabling fluorescence (λex=313 nm, λem=358 nm) or ultraviolet (UV at 303 nm) detection. Reaction conditions such as reaction temperature and reaction time were optimized. Atlantis dC18 column with hydrophilic end capping was selected for the separation of derivatives. Effects of mobile phase compositions such as ion pairs and their concentrations and pH on the retention behaviors and separation results of 9 monosaccharides and 2 uronic acids were investigated. Derivatives of fructose, galactose, glucose, mannose, xylose, arabinose, ribose, galacturonic acid, fucose, glucuronic acid and rhamnose were separated within 42 min, applying tetrabutyl ammonium hydrogen bisulfate (TBAHSO4) as the ion pair reagent. The detection limits were between 3.38×108 mol/L and 176×108 mol/L for fluorescence detection and between 2.55×107 mol/L and 13.4×107mol/L for UV detection. Good linearities were obtained with correlation coefficients (r2) above 0.99. The relative standard deviations (RSDs) of the peak area of the derivatives in 1251 h after derivatization were from 2.5% to 3.9%. This method has been applied for the determination of mono-/disaccharides and uronic acids in spirulina polysaccharide after dissolved in trifluoroacetic acid solution (2 mol/L). The results showed this method is suitable for the analysis of monosaccharide compositions in polysaccharides.

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Simultaneous Analysis of Six Effective Components in the Anti-Alzheimer’s Disease Effective Component Group of Xiao-Xu-Ming Decoction LI Zhonghong, NI Kunyi, DU Guanhua 2007, 25 (1):  80-83.  Abstract ( 2189 )   [Full Text(HTML)] () PDF (171KB) ( 778 )   A method based on high performance liquid chromatography (HPLC) was developed for the quantitative determination of six components in an anti-Alzheimer medicine, Xiao-Xu-Ming Decoction, which is an effective prescription in treating stroke and the sequela of stroke by herbalist doctors for thousands years. The effective component group (ECG) was made according to the results of high-throughput screening, and the curative effect of ECG was validated on aging rats. In this method an ODS column was used. The mobile phase consisted of water-formic acid-ethylenediamine (A; 100∶0.1∶0.1, v/v) and methanol-formic acid (B; 100∶0.05, v/v), eluted with gradient (05 min, 20%B; 5100 min, 20%B40%B; 100140 min, 40%B70%B). The flow rate was 1 mL/min. The detection wavelength was set at 240 nm. Under the above separation conditions, six components belonged to two different categories, indicans and alkaloids, were determined simultaneously. The relationships between the concentrations and the peak areas of these six components were all linear. The recoveries of the six components were 99.1% for paeoniflorin, 99.6% for prim-O-glucosylcimifugin, 98.4% for baicalin, 99.9% for 4′-O-β-D-glucosyl-5-O-methylvisamminol, 99.6% for fangchinoline, and 102.0% for tetrandrine. The relative standard deviations (RSD) were 1.3%, 1.4%, 0.4%, 0.8%, 0.2%, and 1.4%, respectively. This method is simple and reproducible and it can be used for the quality control of the effective component group of Xiao-Xu-Ming Decoction.

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Simultaneous Determination of Polyacetylene Components in Cangzhu by Reversed-Phase High Performance Liquid Chromatography CHEN Yanming, CHOU Guixin, WANG Zhengtao, 2007, 25 (1):  84-87.  Abstract ( 2306 )   [Full Text(HTML)] () PDF (292KB) ( 984 )   In traditional Chinese medicines, atractylodes rhizome (“Cangzhu”in Chinese)is used for the treatment of rheumatic diseases, digestive disorders, mild diarrhea, night-blindness. According to the Pharmacopoeia of China (2005 Edition), Rhizoma Atractylodis is the dried root of Atractylodes lancea (Thunb.) DC. or Atractylodes chinensis (DC.) Koidz. Polyacetylenes is one group of the most important active components in Cangzhu. A reversed-phase high performance liquid chromatographic method was developed for the simultaneous determination of two main polyacetylene components including atractylodin and atractylodinol in Cangzhu.The chromatographic analysis was carried out using a Polaris-C18 column and the mobile phase of acetonitrile-water with the flow rate of 1.0 mL/min. The detection wavelength was set at 340 nm, and column temperature was set at 25 ℃. The detection limits (S/N=3) were 0.069 and 0.016 μg for atractylodin and atractylodinol, respectively. The recoveries of the two polyacetylene components were found in the range of 97.4%104.6%. Thirteen samples collected were determined which includes three species of atractylodes rhizome, A.lancea, A.chinensis, and A.japonica. This rapid and accurate method has been successfully applied to the simultaneous determination of the two polyacetylene components in Cangzhu.

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Isolation and Preparation of Flavonoids from the Leaves of Nelumbo nucifera Gaertn by Preparative Reversed- Phase High Performance Liquid Chromatography TIAN Na, LIU Zhonghua, HUANG Jian’an, LUO Guoan, LIU Shuoqian, LIU Xintao 2007, 25 (1):  88-92.  Abstract ( 2414 )   [Full Text(HTML)] () PDF (280KB) ( 1467 )   It has been confirmed that flavonoids in the leaves of Nelumbo nucifera Gaertn (lotus leaves) have many pharmacological activities. Currently, total flavones in the leaves of Nelumbo nucifera Gaertn have been studied extensively, however, only a few researches were able to investigate the individual components in it. At first, crude extract was obtained from lotus leaves by reflux extraction using 60% ethanol for three times. Then, the concentrated crude extract was separated on a D-101 column (eluted with 70% ethanol) and a polyamide column (step gradient 15% to 90% ethanol). The Fr-1 fraction was obtained from the eluate of 45% ethanol and was subjected to a preparative reversed-phase high performance liquid chromatograph (RP-HPLC) for the isolation of target components. The preparation of the individual flavonoids was carried out on an RP-HPLC with a Symmetry PrepTM C18 column, and the mobile phase was water-acetonitrile at a flow rate of 5.0 mL/min. Three compounds were identified with ultra violet absorbance (UV), infrared (IR), nuclear magnetic resonance (NMR) and mass spectrometry (MS). They were hyperin, isoquercetin and astragalin. To our knowledge that astragalin was the first time successfully isolated from this plant. The purity of the three compounds was all over 97%.

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Application of Fingerprint Chromatogram in Quality Assessment of Apple Cider XU Kangzhen, SONG Jirong, REN Yinghui, MA Haixia, HUANG Jie, DU Xiaodan 2007, 25 (1):  93-95.  Abstract ( 1968 )   [Full Text(HTML)] () PDF (165KB) ( 732 )   Fingerprints of 14 apple cider samples from different manufacturers were studied using high performance liquid chromatography (HPLC) with an electrochemical detector (ECD). The analysis was carried out on a Zorbax SB-C18 column at 30 ℃ with 2% (v/v) methanol aqueous solution-4%(v/v) acetic acid aqueous solution as mobile phase at a flow rate of 0.8 mL/min. The electrochemical detector was set at 0.7 V. By calculating the relative retention times of certain peaks with chlorogenic acid as the reference standard, 8 common peaks in the samples were analyzed. Relative retention times for the common peaks of various samples were calculated, and the similarities of all the samples were figured out through each peak area with the vectorial angle cosine method and correlative coefficient method. The results indicated that apple cider products of the same manufacturer have good similarity, with the similarities greater than 92.7%. According to this experiment, effectual microcosmic information for apple cider analysis was gained through HPLC and ECD. Moreover, this test method will help the analysis and the control of product quality, the development of new products and the establishment of trade standard.

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Study on Capillary Electrophoresis Fingerprints of Flos Lonicerae Japonicae SUN Guoxiang, YANG Hongtao, DENG Xiangyu, SUN Yuqing 2007, 25 (1):  96-100.  Abstract ( 2192 )   [Full Text(HTML)] () PDF (438KB) ( 988 )   The capillary electrophoresis fingerprints(CEFP) of Flos Lonicerae Japonicae was established to control its quality. In the capillary zone electrophoresis (CZE) pattern 50 mmol/L sodium borate contained 20 mmol/L β-cyclodextrin (β-CD) adjusted to pH 8.0 with phosphoric acid was applied as the background electrolyte. The running voltage was 12 kV and the detection wavelength was 254 nm. The Flos Lonicerae Japonicae was extracted by water and the sample solution was injected into the capillary by hydraulic pressure in 15 s. The 18 common peaks were marked according to the emerging rate of 100% and by comparing each fingerprint with the other one among the 13 samples cultivated in different places, in which chlorogenic acid was selected as the reference peak. The CEFP had good precision and reproducibility with the relative standard deviations (RSDs) of the relative migration times less than 3% and the RSDs of the relative peak areas within 6.1%. The novel concepts of the apparent quantitative similarity (R), the quantitative similarity calculated by vector projection (C) and the quantitative similarity (P) were introduced firstly. The good crude drugs should posses two merits as follows: the qualitative similarity (S) which displays the distribution of the chemical constituents in sample should be more than 0.90; the quantitative similarities (R, C, P, Q) that disclose the overall contents of the chemical constituents in sample should be within 80%120%.This method was applied in the quality control practice, and the results showed that the method could be used for the overall quality control of Flos Lonicerae Japonicae and is especially suitable for qualitative and quantitative evaluation of chromatographic fingerprints both in chemical constituent distribution and in contents.

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Separation of Phosphodiester Oligodeoxynucleotides and Phosphorothioate Antisense Oligodeoxynucleotides by Capillary Zone Electrophoresis at Low pH LI Qian, CHEN Rong, SUN Yuqing, HU Yuzhu 2007, 25 (1):  101-106.  Abstract ( 2570 )   [Full Text(HTML)] () PDF (531KB) ( 836 )   Oligodeoxynucleotides (ODNs) may possess biological activity in vivo, and are used for the cancer therapeusis. Synthesized ODNs contains many by-products, and so their purity check and resolution of single-base, i.e., the separation of ODNs differing by one nucleotide in length, become necessary. In this study, capillary zone electrophoresis (CZE) method was developed for the separation of two sets of model compounds of single-stranded oligodeoxynucleotide mixtures (1820 mers), phosphodiester oligodeoxynucleotides (PO-ODNs) and their phosphorothioate modifications (PS-ODNs), with equal sequences differing in a single base. The effects of the CZE operating parameters on the separation were investigated and optimized to further improve the resolution, such as the pH values and the concentrations of running buffer, the varieties and concentrations of additives, the separation voltage as well as the temperature. It was confirmed that the pH value of the buffer played the most important role in the separation, and the urea used as the additive in the system improved significantly the resolution of PS-ODNs. Consequently, the PO-ODNs and PS-ODNs mixtures could be single-based separated on a fused-silica capillary of 50 μm×49.0 cm (40.7 cm of effective length) under the optimum conditions: the running buffer system of 50 mmol/L NaH2PO4-H3PO4(pH 2.24)-7 mol/L urea, the pressure injection of 2 kPa×10 s, the separation voltage of 20 kV, the column temperature of 25 ℃, and the ultraviolet (UV) detection at 260 nm. The average resolutions for the separation of 1819 mers and 1920 mers of PO-ODNs were 4.68 and 3.20, respectively; and the average resolutions for the separation of 1819 mers and 1920 mers of PS-ODNs were 1.23 and 0.81, respectively. The relative standard deviations of the migration time and the resolution were all less than 5%. This method will be useful for the qualification of PO-ODNs and PS-ODNs samples as they are used in antisense drug development due to the relatively easy operation and good reproducibility of the method in comparing with the capillary gel electrophoresis.

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Simultaneous Determination of Twenty-one Organic Acids in Food by Ion Chromatography with Eluent Autogeneration LIN Huaying, LIN Fenghua, SHENG Lina, LI Yidan, ZHANG Qiong 2007, 25 (1):  107-111.  Abstract ( 2760 )   [Full Text(HTML)] () PDF (410KB) ( 1182 )   A novel ion chromatographic method was developed for the simultaneous determination of organic acids in food samples including quinic acid, acetic acid, pyruvic acid, ketosuccinic acid, mannitic acid, lactic acid, succinic acid, malic acid, tartaric acid, oxalic acid, fumaric acid, ascorbic acid, α-ketoglutaric acid, cinnamic acid, salicylic acid, citric acid, isocitric acid, ferulic acid, cis-aconitic acid, trans-aconitic acid, β-coumaric acid. 534 mmol/L KOH produced by an EG40 eluent autogenerator could achieve a flat baseline and lower background conductance when performing gradient elution. The flow rate was 0.62.5 mL/min and the injection volume was 25 μL. The separation was performed on an IonPac AS11 column and detected by suppressed conductivity with self-regenerating suppressor mode. The samples were prepared through extraction, decoloration and filtration before analysis. Twenty-one organic acids showed good linear relationship between the mass concentration and the peak area in the measurement ranges. The correlation coefficients were above 0.999 and the detection limits were 0.0110.188 mg/L, and the average recoveries were 91.5%101.8%. The method is simple and rapid with good accuracy and reproducibility, and has been applied to determine twenty-one organic acids in diversiform samples with satisfactory results.

Technical Notes

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Determination of Perflurooctanoic Acid (PFOA) and Its Salts in Packaging Materials Using LC-MS-MS Method 2007, 25 (1):  115-115.  Abstract ( 1867 )   [Full Text(HTML)] () PDF (71KB) ( 956 )

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Determination of α- lactalbumin and β-lactoglobulin in Whey Protein by Reverse-Phase HPLC(C8) 2007, 25 (1):  116-117.  Abstract ( 1937 )   [Full Text(HTML)] () PDF (145KB) ( 1079 )

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Determination of Trace Nitrite and Nitrate in Seawater by Ion Chromatography 2007, 25 (1):  120-120.  Abstract ( 2178 )   [Full Text(HTML)] () PDF (827KB) ( 1434 )