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Chinese Journal of Chromatography
2008, Vol. 26, No. 2
Online: 30 March 2008

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中药质量控制专栏

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Prospects of the development of quality control technologies for traditional Chinese medicine LIANG Xinmiao, FENG Jiatao, JIN Yu, GUO Zhimou, XU Qing 2008, 26 (2):  130-135.  Abstract ( 2591 )   [Full Text(HTML)] () PDF (123KB) ( 1422 )   Quality control is one of bottleneck problem limiting the applications and development of traditional Chinese medicines (TCMs). In recent years, the research on TCMs has already made a great progress. In this review, the background of quality control is discussed from the requirement of TCMs industry, modernization of TCMs, the requirement of techniques as well as opportunities and challenges in the quality control of TCMs. The significance of quality control to improve the efficiency and safety of TCMs, to promote the development of TCMs industry and the globalization of TCMs are also discussed. The status quo of quality control is reviewed, in which the drawbacks of process control, safety control, the preparation of reference compounds and fingerprint in quality control of TCMs were analyzed. In addition, the technological prospects based on modern separation techniques and detection methods for the quality control of TCMs are put forward, including the key techniques of the quality control, the techniques of safety control, the standard systems of the quality control, the innovative techniques, the techniques for the preparation of reference compounds, the establishment of technique standards, etc.

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Application of chromatography and related techniques in quality evaluation of traditional Chinese medicine WANG Yong, LIANG Qionglin, HU Ping, WANG Yiming, LUO Guoan, 2008, 26 (2):  136-141.  Abstract ( 2370 )   [Full Text(HTML)] () PDF (230KB) ( 974 )   Chemomics, the methodology for the study of traditional Chinese medicines (TCMs) on the substance basis, and chromatographic fingerprinting, the crucial technology of quality evaluation of TCMs, are introduced. The applications of chromatography as well as some related techniques in the information acquisition of TCMs are summarized. Guided by chemomics, with the results of chromatography and multi-component quantification, this research mode is of great significance to the establishment of the quality evaluation system of TCMs.

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Some advances and prospects in fingerprintings of traditional Chinese medicines HAN Yehua, HUO Feifeng, YANG Youyou, LIAO Yiping, LIU Huwei 2008, 26 (2):  142-152.  Abstract ( 2522 )   [Full Text(HTML)] () PDF (259KB) ( 1583 )   The quality control standards are the key points in the modernization of traditional Chinese medicines (TCM), and in recent years, the fingerprinting techniques play an increasingly important role, including fingerprintings based on gas chromatography, liquid chromatography, capillary electrophoresis, spectroscopic methods, and so on. Some advances in this area in the past few years are reviewed and some prospects are discussed in this article.

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Quality control of Chinese herbal medicines with chromatographic fingerprints ZHOU Jianliang, QI Lianwen, LI Ping 2008, 26 (2):  153-159.  Abstract ( 2781 )   [Full Text(HTML)] () PDF (186KB) ( 2063 )   The applications of chromatographic fingerprint in the quality control of Chinese herbal medicines (CHMs), such as chemical fingerprint in the authentication of CHMs, chromatographic pharmacodynamics, biofingerprint and metabolic fingerprint in the efficacy evaluation of CHMs are reviewed. In recent quality control system of CHMs, chemical fingerprint has been a forceful technology in the authentication of CHMs, and chromatographic pharmacodynamics, biofingerprint and metabolic fingerprint have shown advantages in the efficacy evaluation of CHMs because of their correlations with pharmacological activities. Furthermore, the application of chromatographic fingerprint in safety evaluation of CHMs becomes more and more significant.

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Quality control of traditional Chinese medicines by the capillary electrophoresis fingerprint and capillary electrophoresis-mass spectrometry SUN Yuqing, SUN Guoxiang, JIN Yu 2008, 26 (2):  160-165.  Abstract ( 2038 )   [Full Text(HTML)] () PDF (166KB) ( 1279 )   The quality control of traditional Chinese medicines by capillary electrophoresis (CE) fingerprint and CE-mass spectrometry(CE-MS) is reviewed. The optimum experimental conditions of CE, the research and appraisal methods of CE fingerprint for traditional Chinese medicines are also discussed . This review is based on the authors’ work.

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Chromatographic fingerprint and quality control of traditional Chinese medicines YI Lunzhao, WU Hai, LIANG Yizeng 2008, 26 (2):  166-171.  Abstract ( 2415 )   [Full Text(HTML)] () PDF (214KB) ( 1667 )   The development of modern chromatographic technologies and related chemometric methods in the research of chromatographic fingerprint, and their applications in quality control of traditional Chinese medicines (TCMs) are comprehensively reviewed. Furthermore, we preliminarily discuss the quality control methods and their feasibility to guarantee that the TCMs can be used stably and effectively. A new strategy is proposed to establish the comprehensive relationships between chromatographic fingerprints and their pharmacodynamic (toxicity) information with the help of the techniques of modern chromatography, chemometrics and system biology to reveal the working mechanism of TCMs and then to comprehensively control the quality of TCMs.

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Effect of fingerprintology of traditional Chinese medicine (TCM) in the innovative development of TCM SUN Guoxiang, BI Kaishun 2008, 26 (2):  172-179.  Abstract ( 2468 )   [Full Text(HTML)] () PDF (4959KB) ( 1070 )   The background and main task of the system of TCM fingerprintology from holism, systematology and complexity science are elaborately discussed. The fingerprintology of TCM is a novel system, in which the pharmacologic substance bases, mechanism and the law of pharmacokinetics on TCM (herbal medicine) and technologies for other related preparations are systematically and integrally studies. The core position and bridge effect of the fingerprint informatics of TCM were set forth. The system of TCM fingerprintology comprises the fingerprint testology, the fingerprint quality controlology, the fingerprint pharmacodynamics, the fingerprint pharmacokinetic, the fingerprint-pharmaceutics and the biofingerprintology of TCM. The theories and methods of complexity science and system science should be applied in the study of the system. The new mode of the innovative development of TCM is established by breaking through the linear thinking and reduction analysis, highly emphasizing mathematical principles and methods from a integral and systematic point of view. The theories and methods of the TCM fingerprintology are the main forces in the analysis of the leading technology and modernization of TCM. The maturity and perfection of the theories and methods will powerfully support the development of innovative TCM. The ultimate purpose of the system of the TCM fingerprintology is to develope effective, safety and controllable TCMs for human and other beneficial organisms.

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Development of full-quantified fingerprint for quality control of traditional Chinese medicines FENG Jiatao, JIN Yu, WANG Jincheng, XIAO Yuansheng, LIANG Xinmiao 2008, 26 (2):  180-185.  Abstract ( 2229 )   [Full Text(HTML)] () PDF (1948KB) ( 1154 )   Full-quantified fingerprint technique combines the fingerprint technique and multiple-target determination technique. The development of full-quantified fingerprint technique includes the preparation of full-quantified fraction, the quality control in preparation process with fingerprint technique and determination of products. In this paper, the full-quantified fractions of Salvia miltiorrhiza Bge. were prepared by water extraction, deposition with the ethanol, membrane filter, separation on macroporous resin and separation with preparative high performance liquid chromatography (HPLC). Fingerprint technique was used to test the reproducibility of preparation. Three ingredients, protocatechualdehyde, rosmarinic acid, salvianolic acid B were determined and the sum of their contents was more than 50%. The pharmaceutical active compounds were taken as the preparation target. The impurities were removed effectively by multiple preparations, and the specification of full-quantified fraction was improved greatly.

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Determination of three bufogenins in toad venom using reversed-phase high performance liquid chromatography LIU Jihua, WANG Jingrong, YU Boyang 2008, 26 (2):  186-188.  Abstract ( 2226 )   [Full Text(HTML)] () PDF (178KB) ( 898 )   A method for the identification and relative quantification of peptides by capillary reversed-phase liquid chromatography ion-trap tandem mass spectrometry (LC-IT-MS/MS) was established. At first, the peptides were automatically identified by correlating the tandem mass spectra with the peptide sequences from a database. After the quantitative information of peptide ions were extracted from the full-scan MS according to the results of database searching, the peak intensities of the identified peptide ions with different charge states were summed together to define the total intensity of the peptide. Then, the peak intensities of the same peptide in the replicate analysis of the same sample were averaged and assigned as the abundance of the peptide. Finally, the abundances of the common peptide in the analysis of different samples were compared. This approach relied on the analytical reproducibility and linearity of signal versus molecular concentration. As a measure of the analytical reproducibility for tryptic peptides sampling, the median of the relative standard deviation of 35% was determined for 50 common peptides from 3 replicate analysis of 200 fmol bovine serum albumin (BSA) digest. The method was further illustrated using digested mixtures of BSA and myoglobin as follows. The BSA digest was gradually diluted while the myoglobin digest was present in the mixtures at constant level. This study revealed that the abundance of the variable BSA peptides increased linearly (trend line r2＞0.97) with increasing amount from 10 to 1000 fmol, while the abundances of the constant peptides from myoglobin remained approximately the same. In the present method, chemical derivatization steps are not needed to create an internal standard, as in isotope-coded affinity tag or similar methods. This method provides an alternative approach for differential analysis of peptides in biological samples.

Articles

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Identification and relative quantification of peptides by capillary reversed-phase liquid chromatography-tandem mass spectrometry LI Xin, JIANG Xinning, ZOU Hanfa 2008, 26 (2):  189-194.  Abstract ( 2205 )   [Full Text(HTML)] () PDF (616KB) ( 958 )   A method for the identification and relative quantification of peptides by capillary reversed-phase liquid chromatography ion-trap tandem mass spectrometry (LC-IT-MS/MS) was established. At first, the peptides were automatically identified by correlating the tandem mass spectra with the peptide sequences from a database. After the quantitative information of peptide ions were extracted from the full-scan MS according to the results of database searching, the peak intensities of the identified peptide ions with different charge states were summed together to define the total intensity of the peptide. Then, the peak intensities of the same peptide in the replicate analysis of the same sample were averaged and assigned as the abundance of the peptide. Finally, the abundances of the common peptide in the analysis of different samples were compared. This approach relied on the analytical reproducibility and linearity of signal versus molecular concentration. As a measure of the analytical reproducibility for tryptic peptides sampling, the median of the relative standard deviation of 35% was determined for 50 common peptides from 3 replicate analysis of 200 fmol bovine serum albumin (BSA) digest. The method was further illustrated using digested mixtures of BSA and myoglobin as follows. The BSA digest was gradually diluted while the myoglobin digest was present in the mixtures at constant level. This study revealed that the abundance of the variable BSA peptides increased linearly (trend line r2＞0.97) with increasing amount from 10 to 1000 fmol, while the abundances of the constant peptides from myoglobin remained approximately the same. In the present method, chemical derivatization steps are not needed to create an internal standard, as in isotope-coded affinity tag or similar methods. This method provides an alternative approach for differential analysis of peptides in biological samples.

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Phosphopeptide enrichment strategy based on strong cation exchange chromatography SUI Shaohui, WANG Jinglan, LU Zhuang, CAI Yun, ZHANG Yangjun, YU Wenfeng, QIAN Xiaohong 2008, 26 (2):  195-199.  Abstract ( 2422 )   [Full Text(HTML)] () PDF (690KB) ( 1310 )   The routine analysis of phosphoproteomics needs effective and specific enrichment methods. The strong cation exchange chromatography (SCX) separation conditions, including the buffer solution and the separation gradient, were studied to enrich the phosphopeptides in a short time. Firstly, the tryptic peptides of standard protein mixtures (bovine α-casein and β-casein, chicken egg ovalbumin) were used to optimize the SCX strategy. Then, this method was applied to the complicated samples, the tryptic peptides from yeast. The experimental results showed that the phosphopeptides were eluted before 30 min in the optimized SCX systems with less interference from nonphosphopeptides. Phosphopeptides were successfully separated in a short time, and the ion signals corresponding to phosphopeptides were accordingly increased during mass spectrometric analysis. It was indicated that the optimized SCX separation system could be used as a simple enrichment method for the separation of phosphopeptides, especially for phosphopeptides in the complex real samples, in a short time, and to increase the relative abundance of phosphopeptides in the detection fraction. This study provides the pragmatic technique for phosphoproteomics analysis on a large-scale.

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Preparation of 1-(2-naphthyl)-3-methyl-5-pyrazolone as pre-column derivatization reagent for the determination of saccharides using high performance liquid chromatography-mass spectrometry SUN Zhiwei, LIU Lingjun, HU Baojun, SHENG Xiao, WANG Xiaoyan, SUO Yourui, YOU Jinmao, 2008, 26 (2):  200-205.  Abstract ( 2420 )   [Full Text(HTML)] () PDF (740KB) ( 1045 )   Eight saccharides were derivatized using 1-(2-naphthyl)-3-methyl-5-pyrazolone (NMP) as pre-column derivatizing reagent， and separated on a reversed-phase Hypersil ODS 2 column (4.6 mm×200 mm, 5 μm), by high performance liquid chromatography (HPLC) in conjunction with a gradient elution, detected by a diode array detector (DAD), and identified by electrospray ionization-mass spectrometry (ESI-MS) in positive ion mode. NMP reacted with reductive saccharides easily in the presence of 17% ammonia water at 70 ℃. All linear correlation coefficients for saccharide derivatives were over 0.9985. The detection limits （at signal-to-noise of 3∶1） were 0.58-1.1 pmol for saccharide derivatives. The characteristic fragment ions, especially m/z 473, from the cleavage of NMP-labeled saccharides exhibited high regularity for the identification of the composition of saccharide mixture. The established method is sensitive and repeatable for the determination of saccharides.

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Preparation and identification of recombinant human interferon-γ WU Dan, GAO Dong, BAI Quan, GENG Xindu 2008, 26 (2):  206-211.  Abstract ( 2088 )   [Full Text(HTML)] () PDF (1496KB) ( 840 )   The renaturation with simultaneous purification of recombinant human interferon-γ (rhIFN-γ) expressed as inclusion bodies in Escherichia coli (E.coli) was accomplished by the stationary phase of hydrophobic interaction chromatography (STHIC) with the end group of poly(ethylene glycol) （PEG）(PEG200) packed in a chromatographic column and a chromatographic pie by nonlinear gradient, separately. In order to provide more selections for the chromatographic separation of rhIFN-γ from different sources, the chromatographic behavior of rhIFN-γ in reversed-phase liquid chromatography, ion-exchange chromatography and immobilized-nickel affinity chromatography were also studied. The fraction of the renatured and purified rhIFN-γ from HIC was desalted by the size exclusion chromatography, subsequently freeze-dried to powder. With matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS), monomeric and dimeric rhIFN-γ were found in the powder due to the freeze-dried process and their relative molecular masses were 17184.0 and 34204.4, respectively. With the bioactivity assay by cytopathic effect inhibition (CPEI), the specific bioactivity of rhIFN-γ was 9.5×108 IU/mg, which was higher than that of the required criteria in the pharmacopoeia of China, because the presence of dimeric rhIFN-γ which has much higher specific bioactivity than its monomer in the powder. The obtained mass recovery, purity, specific bioactivity of the purified monomeric rhIFN-γ were 93.7%, ＞95%, and 4.3×107 IU/mg, respectively. The results showed that the renaturation with simultaneous purification of rhIFN-γ by PEG200-STHIC is a kind of efficient method.

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Extraction, preparation and identification of volatile compounds in Changyu XO brandy ZHAO Yuping, LI Jiming, XU Yan, DUAN Hui, FAN Wenlai, ZHAO Guang’ao 2008, 26 (2):  212-222.  Abstract ( 2795 )   [Full Text(HTML)] () PDF (509KB) ( 1008 )   A method for the preparation of volatile compounds in Changyu XO brandy was established. The volatile compounds were extracted using liquid-liquid extraction and then were separated into two fractions, namely, the acidic/water-soluble fraction and the neutral/basic fraction. The neutral/basic fraction was furthermore separated into 4 fractions using silica gel normal phase chromatography, and each fraction was then concentrated and analyzed using gas chromatography-mass spectrometry (GC-MS). In comparison with the pure standards and the retention indices (RIs) reported in the literature, a total of 302 volatile compounds were identified in Changyu XO brandy, including 30 alcohols, 35 aldehydes and ketones, 20 carboxylic acids, 104 esters, 24 substituted benzenes and derivatives, 14 phenolic derivatives, 14 acetals, 16 furan derivatives, 22 terpenic and norisoprenoidic derivatives and 23 others. It was demonstrated that this method of preparation was effective for the separation and concentration of volatile compounds in Changyu XO brandy.

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Determination of tropane alkaloid components in Przewalskia tangutica Maxim. by capillary electrophoresis with electrochemiluminescence detection REN Xiaona, MA Yongjun, ZHOU Min, HUO Shuhui, YAO Junli, CHEN Hui 2008, 26 (2):  223-227.  Abstract ( 2630 )   [Full Text(HTML)] () PDF (409KB) ( 1418 )   Based on an Eu-PB modified platinum electrode as the working electrode, a method for the simultaneous determination of the four tropane alkaloids, anisodamine, scopolamine, atropine and anisodine, by capillary electrophoresis with electrochemiluminescence detection (CE-ECL) has been established. The effects of several factors, such as the detection potential, the acidity and concentration of the running buffer, and the content of the methanol additive were investigated for the improvement of separation ability and detection sensitivity. Under the optimized conditions, these four components could be fully separated from each other in a 20 mmol/L phosphate (pH 8.0) containing 7% (v/v) methanol buffer within 6 min. The relative standard deviations of the peak area and migration time were less than 5.0% and 1.1% (n=12) respectively for all the four compounds. Thus, the method has been successfully applied to the determination of anisodamine, scopolamine in Przewalskia tangutica Maxim. The average amounts of 27.8 g/kg anisodamine and 4.43 g/kg scopolamine were found in the herbal rootstalk sample. The recoveries of the tropane alkaloids were 97.8%-102%.

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Determination of β-adrenergic agonists in pig urine and pig fodder using miniaturized capillary electrophoresis with electrochemical detection WANG Weiyu, ZHANG Yulian, XING Xiaoping, WANG Jinyan, SHI Xue, YE Jiannong 2008, 26 (2):  228-231.  Abstract ( 2511 )   [Full Text(HTML)] () PDF (322KB) ( 1468 )   A method of miniaturized capillary electrophoresis with electrochemical detection has been developed for the determination of β-adrenergic agonists in pig urine and pig fodder. Several important factors, including running buffer acidity, separation voltage, working electrode potential, etc., were evaluated to acquire optimum analysis conditions. Under the selected optimum conditions, these analytes can be well separated in 7 min. Good linear relationship was established between the peak current and the concentration of each analyte over 3 orders of magnitude. The detection limits ranged from 1.20×10-7 to 2.06×10-7 g/mL (S/N=3). The proposed method has been successfully applied for the determination of β-adrenergic agonist in pig urine and pig fodder with satisfactory results, providing a useful monitoring method for food safety.

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Selection of back-ground electrolyte in capillary zone electrophoresis by triangle and tetrahedron optimization methods SUN Guoxiang, SONG Wenjing, LIN Ting 2008, 26 (2):  232-236.  Abstract ( 2779 )   [Full Text(HTML)] () PDF (522KB) ( 825 )   The triangle and tetrahedron optimization methods were developed for the selection of back-ground electrolyte (BGE) in capillary zone electrophoresis (CZE). Chromatographic fingerprint index F and chromatographic fingerprint relative index Fr were used as the objective functions for the evaluation, and the extract of Saussurea involucrate by water was used as the sample. The BGE was composed of borax, boric acid, dibasic sodium phosphate and sodium dihydrogen phosphate solution with different concentrations using triangle and tetrahedron optimization methods. Re-optimization was carried out by adding organic modifier to the BGE and adjusting the pH value. In triangle method, when 50 mmol/L borax-150 mmol/L sodium dihydrogen phosphate (containing 3% acetonitrile) ( 1∶1, v/v) was used as BGE, the isolation was considered to be satisfactory. In tetrahedron method, the best BGE was 50 mmol/L borax-150 mmol/L sodium dihydrogen phosphate-200 mmol/L boric acid (1∶1∶2, v/v/v; adjusting the pH value to 8.55 by 0.1 mol/L sodium hydroxide). There were 28 peaks and 25 peaks under the different conditions respectively. The results showed that the methods could be applied to the selection of BGE in CZE of the extract of traditional Chinese medicine by water or ethanol.

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Separation of geometrical isomers of ｛Fe［3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine］3｝2+ (［Fe(PDT)3］2+) using ion-pair reversed-phase high performance liquid chromatography ZHU Weihuang, WU Fengchang, HUANG Tinglin 2008, 26 (2):  237-241.  Abstract ( 2776 )   [Full Text(HTML)] () PDF (526KB) ( 807 )   A method has been developed for the separation of two geometrical isomers of the ｛Fe［3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine］3｝2+ (［Fe(PDT)3］2+) using ion-pair reversed-phase high performance liquid chromatography (RP-HPLC). The effects of the chromatographic conditions, such as the content of acetonitrile and the type and concentration of the ion-pair reagents (sodium perchlorate (NaClO4) or sodium dodecyl sulfate (SDS)) in the binary mobile phase (acetonitrile and water), on the retention factor (k), resolution, and selectivity were discussed. It was found that no matter how the ion-pair reagent was NaClO4 or SDS at different concentrations, the acetonitrile content in the mobile phase has good linear regression equations with the ln k of the two isomers. It was also observed that SDS showed more positive effect on the k of the two geometrical isomers than that of NaClO4. Moreover, the separation of the two isomers in the ternary mobile phase (acetonitrile, methanol and water) was developed. The chromatographic conditions, including the content of the organic modifier (acetonitrile and methanol) and the type and concentration of the ion-pair reagents (SDS and NaClO4), were optimized. Two geometrical isomers were rapidly and successfully separated under the optimized conditions, which used acetonitrile/methanol/water (20∶50∶30, v/v/v) as the mobile phase and 60 mmol/L NaClO4 as the ion-pair reagent. Good linear regression equations between the peak areas and concentrations for the two isomers were obtained. The detection limits of the fac-isomer and mer-isomer were 4.28 and 3.44 ng/mL (S/N＝3), respectively.

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Preparation and characterization of poly(N-isopropylacryl-amide) bonded silica gel stationary phase XU Ronglai, YANG Tonghua, DONG Wei 2008, 26 (2):  246-249.  Abstract ( 2381 )   [Full Text(HTML)] () PDF (424KB) ( 1003 )   A thermal sensitive bonded stationary phase, poly(N-isopropylacrylamide) bonded silica gel stationary phase (SI-PNIPAM), was prepared by reacting silica gel with 3-mercaptopropyltrimethoxysilane (MPS). The characterization of the prepared packings was carried out with elemental analysis and Fourier transform infrared (FT-IR) spectroscopy. The chromatographic evaluations were carried out by testing with polycyclic aromatic hydrocarbons and basic compounds using methanol-water as a binary mobile phase. The applicable range of pH and stability of SI-PNIPAM were also evaluated. The results showed that the stationary phase has excellent chromatographic properties, thermal-responsibility and resistance to hydrolysis between pH 2.5 and 7.5. It can be used to separate basic solutes efficiently due to the existence of the special structure containing internal polar amide group contributing to restraining the activity of the residual silanol group below the lower-critical-solution temperature (LCST).

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Determination of aromatic hydrocarbon types in diesel oil using high performance liquid chromatography with photodiode array detection LIN Yu, LI Yi, BAI Zhengwei, HE Chengyue, ZHANG Qi 2008, 26 (2):  250-253.  Abstract ( 2094 )   [Full Text(HTML)] () PDF (1508KB) ( 854 )   When using ASTM D6591 to determine the content of aromatic hydrocarbons in diesel oil, a photodiode array detector (PDAD) was used to monitor the separation of aromatic hydrocarbons. The influence of back flush time B was studied and it was observed the results of di-aromatic hydrocarbons or poly-aromatic hydrocarbons will give errors when the back flush time is more than B±0.2 min. The PDAD can also be used to determine the best cutting time between mono-aromatic hydrocarbons and di-aromatic hydrocarbons, when the separation was not baseline resolved.

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Determination of amphetamines in human urine using microwave extraction-gas chromatography WANG Jifen, SUN Hongfeng, YE Nengsheng, GU Xuexin, LI Wenjun, LI Ying 2008, 26 (2):  254-258.  Abstract ( 2246 )   [Full Text(HTML)] () PDF (614KB) ( 1021 )   A method has been developed for the determination of methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA) and 3,4-methylenedioxymethamphetamine (MDMA) in human urine using microwave extraction-gas chromatography(GC). To improve the extraction efficiency, experimental parameters of the extraction, including extraction solvent and its amount, pH value of the urine sample, extraction time and temperature were investigated. The optimal conditions were as follows: the pH value of urine sample at pH 12, cyclohexane as extraction solvent, extraction at 40 ℃ for 10 min. The average recoveries of MA, MDA and MDMA with this extraction method were 92.25%, 85.94% and 91.50%, the relative standard deviations were 5.5%, 5.5% and 6.1% (n=5), and the limits of detection were 10, 20 and 20 ng/mL, respectively. Using this method, MA, MDA and MDMA 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 simultaneous determination of MA, MDA and MDMA in urine samples.

Technical Notes

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High performance liquid chromatographic separation of oxybutynin enantiomers using chiral mobile phase additive GUO Na, GAO Xinxing, XU Guofang, GUO Xingjie 2008, 26 (2):  259-261.  Abstract ( 2583 )   [Full Text(HTML)] () PDF (190KB) ( 1182 )   A simple and effective method for the separation of oxybutynin enantiomers was developed using high performance liquid chromatography with hydroxypropyl-β-cyclodextrin (HP-β-CD) as the chiral mobile phase additive and a C18 reversed-phase column as the stationary phase. β-CD and HP-β-CD were investigated as chiral mobile phase additives separately. The results showed that oxybutynin enantiomers could not be separated when adding β-CD in the mobile phase, but optimal resolution was obtained when using HP-β-CD as the chiral mobile phase additive. Excellent enantioseparation was achieved with the mobile phase composed of 30 mmol/L KH2PO4-acetonitrile(80∶20, v/v) mixed with 60 mmol/L HP-β-CD at pH 4.0. The detection wavelength was set at 223 nm and the column temperature was set at 28 ℃ with a flow rate of 0.8 mL/min.Under the optimized conditions, the resolution of enantiomers was 1.54 and the limit of quantitation was 1.0 ng. Comparing with chiral stationary phase chromatography, the method was simple, economic and considerably reproducible.

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Identification of concentration and brand for products using differential gel permeation chromatography WANG Qingguo, LI Xiaowen, LIU Bo, CAI Lixing, CHENG Rongshi, 2008, 26 (2):  262-265.  Abstract ( 1845 )   [Full Text(HTML)] () PDF (353KB) ( 794 )   In differential gel permeation chromatographic method (D-GPC), a standard solution and an analyzed solution are used as the eluent and injected solution, respectively. It can determine the minute differences between them. When the analyzed solution and the standard solution are identical, a null signal is given, otherwise the nonzero signal tells the detailed differences between them. Two examples, the concentration identification of five polyethylene glycol 200 (PEG200) solutions and the brand identification of three brands of beers, are given to show the application of the D-GPC method. The potential applications of the D-GPC method in quality control and the identification of counterfeit products are also discussed.