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Chinese Journal of Chromatography
2011, Vol. 29, No. 06
Online: 28 June 2011

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Microchip-based reversed-phase liquid chromatography-tandem mass spectrometry platform for protein analysis LIANG Yu1,2, WU Ci1,2, DAI Zhongpeng1, LIANG Zuocheng1, LIANG Zhen1, ZHANG Lihua1*, ZHANG Yukui1 2011, 29 (06):  469-474.  DOI: 10.3724/SP.J.1123.2011.00469 Abstract ( 2429 )   [Full Text(HTML)] () PDF (274KB) ( 581 )   Due to the high throughput and high sensitivity, the hyphenation of microchip-based high performance liquid chromatography with tandem mass spectrometry has been paid much attention. In our recent work, with poly(lauryl methacrylate-co-trimethylolpropane trimethacrylate) monolithic materials prepared in microchannels as trap and separation columns, conventional micro-liquid chromatography pumps and valves for fluidic control, and a small-bore open-tube capillary attached to the outlet channel as chip-mass spectrometer (MS) interface, the microchip-based reversed-phase liquid chromatography-tandem mass spectrometry (RPLC-MS/MS) platform was established, and applied for the identification of proteins. By such platform, 100 ng digest of bovine serum albumin (BSA) was successfully analyzed with the sequence coverages as 39.37%, 37.89% and 34.10% (with the relative standard deviation (RSD) of 7.3%) in three runs, separately. To evaluate the chip-to-chip reproducibility, BSA was identified by such platform with the microchips from different batches containing trap column, separation column and chip-MS interface. The obtained sequence coverage and the number of peptides identified were comparable. All these results showed high sensitivity and good reproducibility of such platform, demonstrating the great potential for rapid protein analysis.

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Determination of sitagliptin phosphate in rat plasma by ultra high performance liquid chromatography-tandem mass spectrometry TANG Yao1, LI Xiang2, WEN Nie1, SUN Xu1, ZHU Ling1, YU Min1, LI Zuogang1*, LI Bo1 2011, 29 (06):  475-480.  DOI: 10.3724/SP.J.1123.2011.00475 Abstract ( 2804 )   [Full Text(HTML)] () PDF (214KB) ( 723 )   an ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the determination of sitagliptin phosphate in rat plasma was established. The blank rat plasma sample added with sitagliptin phosphate and the internal standard (fluoxetine) standard solution were prepared. Methanol was added in the sample for the deproteinization. Then the sample was vortex-mixed and centrifuged. The clear supernatant was used for the analysis of UPLC-MS/MS. A Thermo Hypersil Gold C18 column (50 mm×2.1 mm, 1.9 μm) was employed with a guard column of Phenomenex Security Guard C18 column (4 mm×3.0 mm), and the column temperature was set at 35 ℃. The gradient elution of acetonitrile and water (containing 0.05% (v/v) formic acid) as mobile phases was performed at a flow rate of 200 μL/min, and a rapid separation was completed in 5 min. The electrospray was operated in the positive ionization mode and the sitagliptin phosphate and fluoxetine were identified by selected reaction monitoring (SRM) mode, and the monitoring ions of them were m/z 408.0→235.0 and m/z 310.0→148.0, respectively, which were used to qualify and quantity the targets by the method of matrix-matched standard solution. The calibration curve showed good linearity within the concentrations of 1 to 1000 μg/L (r=0.9991); the limit of detection was 0.2 μg/L. The mean recoveries were from 85% to 115% at the spiked levels of 5, 50 and 500 μg/L; the relative standard deviations (RSDs) of intra- and inter-day of variation were both less than 15%, which can meet the determination requirements of biological samples. Then the method was initially used for the determination of sitagliptin phosphate in SD rat plasma after the administration of a single intravenous injection dose of sitagliptin phosphate. The method is rapid, sensitive, convenient and reproducible in the determination of sitagliptin phosphate, and can be used for the pharmacokinetics research of sitagliptin phosphate in plasma.

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Comparison of different buffer systems for separation of 15 nucleosides by capillary electrophoresis 2011, 29 (06):  481-487.  DOI: 10.3724/SP.J.1123.2011.00481 Abstract ( 2325 )   [Full Text(HTML)] () PDF (257KB) ( 583 )   The most suitable background electrolytes (BGEs) for simultaneous separation of 15 nucleosides by different modes of capillary electrophoresis (CE) were obtained. Various modes of CE were performed including capillary zone electrophoresis (CZE), capillary electrophoresis-electrospray ionization-time of flight mass spectrometry (CE-ESI-TOF/MS) and micellar electrokinetic chromatography (MEKC). The electrolyte buffers using sodium tetraborate decahydrate, disodium hydrogen phosphate, sodium acetate, sodium bicarbonate, ammonium acetate or 1, 2-diamino-ethane (DEA) were tested, and the best of them were systematically optimized. In CZE mode, the nucleosides could not be separated completely with sodium tetraborate decahydrate or disodium hydrogen phosphate as BGEs, demonstrating the limited applicability of the two buffer systems for complex samples. However, with 300 mmol/L DEA (containing 2% acetone) as BGE, 15 nucleosides could be separated with good resolution and peak shape, which proved that the DEA buffer was most suitable in CZE. The best buffer system in MEKC mode was 25 mmol/L disodium hydrogen phosphate with 70 mmol/L sodium dodecyl sulfate (SDS), and it was successfully applied for the separation of the nucleosides in Chinese Anthopleura lanthogrammica Berkly. The optimum buffer system for CE-ESI-TOF/MS analysis was 20 mmol/L ammonium acetate (pH 10.0). In the positive ion mode, the MS signals of each compound were better than those in the literature using DEA as BGE. The results of this study demonstrated the applicability of different buffer systems for the simultaneous separation of 15 nucleosides, and were helpful for the development of CE method in complex sample separation.

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An ultra performance liquid chromatography-time-of-flight-mass spectrometric method for fast analysis of ginsenosides in Panax ginseng root HU Chunxiu1,2, KONG Hongwei1, ZHU Chao2,4, WEI Heng3, Thomas HANKEMEIER2, Jan van der GREEF2,3, WANG Mei3, XU Guowang1* 2011, 29 (06):  488-494.  DOI: 10.3724/SP.J.1123.2011.00488 Abstract ( 2206 )   [Full Text(HTML)] () PDF (260KB) ( 668 )   A method for fast analysis of ginsenosides in Panax ginseng roots was developed using ultra performance liquid chromatography-time-of-flight-mass spectrometry (UPLC-TOF-MS). The column used was HSS T3 (100 mm×2.1 mm, 1.8 μm). The mobile phase consisted of 15 mmol/L ammonium formate and acetonitrile, eluted with the gradient program. The separations of 9 ginsenoside standards and ginseng root extracts were achieved. Based on the MS/MS fragments and accurate masses of the target compounds and with combination of the MS/MS fragments of the 9 ginsenoside standards, 27 ginsenosides were identified from the extracts of the ginseng roots. The validation of the analytical method was thoroughly investigated with 9 ginsenoside standards. It was found that 9 ginsenosides had a better linearity in 0.04~9.00 mg/L. The recoveries at the three spiked levels (low, medium and high) were 90%~100%, 98%~104% and 96%~103%, respectively. The relative standard deviations (RSDs) of the peak area ratio of 9 ginsenoside standards to internal standard at the medium spiked level were not more than 11.3%, which were satisfactory for profiling analysis of herb extracts. This method is characterized by its high resolution, rapidness, simplicity and reliability, and has been successfully applied to the evaluation of the differentiation between 2- and 6-year-old ginseng roots. It can be expected that this method is also useful for the fast determination of the ginsenosides in other ginseng related samples.

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Determination of 14 mycotoxins in Chinese herbs by liquid chromatography-tandem mass spectrometry with immunoaffinity purification 2011, 29 (06):  495-500.  DOI: 10.3724/SP.J.1123.2011.00495 Abstract ( 2796 )   [Full Text(HTML)] () PDF (222KB) ( 734 )   A method was developed for the determination of 14 mycotoxins, aflatoxins, T-2, HT-2, fumonisins, ochratoxin A, zearalenone, etc. in Chinese herbs by liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS). The sample was extracted with phosphate buffer solution (PBS) and methanol in turn, and then purified by a high selective multifunctional immunoaffinity column. The column was washed by PBS (containing 0.1% Twain) and water, and then eluted by methanol. The eluate was dried under nitrogen, dissolved in methanol-10 mmol/L NH4Ac （40:60, v/v） solution. The mycotoxins were separated on a Waters Xterra C18 MS column (100 mm×2.1 mm, 3.5 μm) and detected by MS/MS. The limits of quantification (LOQs) of the 14 mycotoxins were from 1.0 to 5.0 μg/kg. The average recoveries of the 14 mycotoxins spiked in Chinese herbs (Ginseng, Campanulaceae, Radix and Ophiopogonis) ranged from 71.9% to 99.7% at the three spiked levels of 1.0, 5.0, 10.0 μg/kg, and the relative standard deviations (RSDs, n=6) were between 4.8% and 15.8%. The method is rapid, sensitive and accurate, and suitable for the determination of the 14 mycotoxins in Chinese medicines. The quantification limits of aflatoxins can meet the domestic and foreign requirements.

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Determination of 7 nipagin ester preservatives in leather by ultra performance liquid chromatography-tandem mass spectrometry coupled with gel permeation chromatographic clean-up 2011, 29 (06):  501-506.  DOI: 10.3724/SP.J.1123.2011.00501 Abstract ( 2263 )   [Full Text(HTML)] () PDF (233KB) ( 535 )   A novel method has been developed for the rapid separation and determination of 7 nipagin ester preservatives in leather by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) coupled with gel permeation chromatographic (GPC) clean-up. Nipagin ester preservatives in leather were extracted by ultrasonic extraction with methanol. The extract was dried by a rotavapor and purified by GPC, then redissolved in the solvent of methanol-water (1:1, v/v). The chromatographic analysis was performed on an Acquity UPLC BEH C18 column (50 mm×2.1 mm, 1.7 μm) with a gradient elution of methanol and water as the mobile phases. The analytes were detected by electrospray ionization (ESI) tandem mass spectrometry with multiple reaction monitoring (MRM) in negative ion mode. Good linearity (r＞ 0.99) was observed between 0.1 and 1.0 mg/L for all the analytes. The recoveries and relative standard deviations (RSDs) were checked by spiking samples with the 7 nipagin ester preservatives at the three levels of 0.5, 1.0 and 3.0 mg/kg. The average recoveries of the 7 nipagin ester preservatives were from (79.44±5.67)% to (98.07±9.50)%. The precision values expressed as RSD ranged from 4.24% to 14.00% (n=6). The limits of detection were 4~12 μg/kg and the limits of quantification were 13.2~39.6 μg/kg for the analytes. The method is simple, rapid, sensitive and accurate, and suitable for the quantitative determination and confirmation of 7 nipagin ester preservatives in leather.

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Determination of distearyl dimethyl ammonium chloride in textiles by reversed-phase and normal-phase liquid chromatography-electrospray ionizationtandem mass spectrometry DING Youchao1, SHEN Xiaoping2, WU Xiaoqiong3, WU Lina1, CAO Xizhong1* 2011, 29 (06):  507-512.  DOI: 10.3724/SP.J.1123.2011.00507 Abstract ( 2401 )   [Full Text(HTML)] () PDF (233KB) ( 596 )   A method of reversed-phase (RP)/normal-phase (NP)-liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was developed for the determination of distearyl dimethyl ammonium chloride (DSDMAC) in textiles. The DSDMAC in textile was extracted by ultrasound-assisted extraction using methanol as extraction solvent under the conditions of 70 ℃ and 420 W within 30 min. The three quaternary ammonium compounds of DSDMAC were detected by LC-MS/MS in the selective reaction monitoring (SRM) mode. The limits of detection (LODs) (S/N=3) of DSDMAC detected by RPLC-MS/MS and NPLC-MS/MS based on an amino-column were 0.1 mg/kg and 0.01 mg/kg, respectively. The recoveries of DSDMAC spiked in the eight different types of blank fabrics ranged from 85.5% to 103% with the relative standard deviations (RSDs) of 4.18%~12.8% (n=5) by RPLC-MS/MS method. Five laboratories were invited to take part in the validation of the method, and the RSDs of inter-lab were 7.3%~9.4% on two reference samples. The method is fast, accurate and reproducible, and can meet the demands of the determination of DSDMAC in textiles.

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Determination of 3 isothiazolinone preservatives in toys using liquid chromatography-tandem mass spectrometry YANG Rongjing1*, WEI Biwen1, YU Wenjia1, GAO Huan1, SUN Xiaojuan2 2011, 29 (06):  513-516.  DOI: 10.3724/SP.J.1123.2011.00513 Abstract ( 3122 )   [Full Text(HTML)] () PDF (153KB) ( 624 )   The presence of isothiazolinones in toys is severely restricted in European Toy Safety Directive because of their allergenicity. A rapid analytical method for the determination of isothiazolinones (2-Methyl-4-isothiazolin-3-one, 5-Chloro-2-methyl-4-isothiazolin-3-one and 1,2-Benzylisothiazolin-3-one) in toys by liquid chromatography-tandem mass spectrometry has been developed. After ultrasonic extraction in water, samples were analyzed by LC-MS/MS. Methanol:water(15:85, V/V) isocratic elution was used as mobile phase. The linear ranges of calibration curves were 2.0 μg/L ~1 000 μg/L, and the limits of quantification for this method were 0.04 mg/kg for all the analytes employing selected-reaction monitoring (SRM) mass spectrometry. While for the recommended method in EN71-11:2005, the limit of quantification for 1,2-Benzylisothiazolin-3-one was 5 mg/kg, indicating that the sensitivity of this method was beyond that of the recommended method. The recoveries for two types of standard spiked samples were in the range of 95.9%~105.2% and 94.7%~102.8%, respectively, and the relative standard deviations ranged from 3.04% to 4.96% and 2.36% to 4.79%, respectively. The method was applied to ten toy samples, and the precision and sensitivity could meet the requirements of the determinations of isothiazolinones in toys in EN71-9:2005.

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Determination of aflatoxins in cereals and oils by liquid chromatography-triple quadrupole tandem mass spectrometry WANG Xiupin1,2,3, LI Peiwu1,2,3*, YANG Yang4, ZHANG Wen1,3, ZHANG Qi1,3, FAN Sufang1,3, YU Li1,2,3, WANG Lin1,2,3, CHEN Xiaomei1,2,3, LI Ying1,2,3, JIANG Jun1,2,3 2011, 29 (06):  517-522.  DOI: 10.3724/SP.J.1123.2011.00517 Abstract ( 2450 )   [Full Text(HTML)] () PDF (239KB) ( 566 )   The high performance liquid chromatography (HPLC)-triple quadrupole tandem mass spectrometry was applied for the determination of the aflatoxins: B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2), in cereals and oils. The samples were first extracted by ultrasonic method. The optimized conditions of ultrasonic extraction were as follows: temperature of 50 ℃, extraction time of 3 min, methanol-water (containing 40 g/L NaCl) (80:20, v/v) solution as the medium and a ratio of sample to solvent of 1:3 (g:mL). The extracts were then purified using an immunoaffinity column. The separation was performed on a C18 column with mobile phases of 10 mmol/L ammonium acetate and methanol in gradient elution. The sensitive detection of the four AFT compounds by electrospray ionization mass spectrometry (ESI-MS) was carried out in selected reaction monitoring (SRM) mode with aflatoxin M1 (AFM1) as the internal standard. Under the optimized conditions, the limits of detection of AFB1, AFB2, AFG1 and AFG2 were 0.002, 0.004, 0.004 and 0.012 μg/kg, respectively. The recoveries of aflatoxins in different spiked cereals and oils were in the range from 87% to 111%. The intra-day and inter-day precisions were not more than 6.7% and 5.6%, respectively. In comparison with the external standard method, this method can effectively inhibit the matrix effects, and greatly improve the accuracy.

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Determination of 41 hormones in cereal feeds by liquid chromatography-tandem mass spectrometry ZHANG Yi1, LAN Fang1*, ZHANG Feng2, SHEN Jincan1, CHU Xiaogang2 2011, 29 (06):  523-534.  DOI: 10.3724/SP.J.1123.2011.00523 Abstract ( 2138 )   [Full Text(HTML)] () PDF (386KB) ( 669 )   A method was developed for the determination of 10 androgens, 11 progesterones, 10 glucocorticoids, 5 estrogens and 5 resorcylic acid lactones in cereal feeds by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Ethyl acetate was used to extract the sample, and the mixed QuEChERS sorbents were dispersed for purification. The extract was separated by a C18 column and detected in positive or negative multiple reaction monitoring (MRM) mode. With the optimal conditions, the linear ranges of 41 hormones were 5.0~200.0 μg/kg with the correlation coefficients above 0.99 and the limits of quantification (LOQs, S/N≥10) were 0.123~2.72 μg/kg. The method validation was carried out at three spiking levels, and the recoveries were 70.3%~118.1% for soybean meals with the relative standard deviations (RSDs) of 0.82%~19.5%, and 76.1%~122.8% for corn meals with the RSD of 1.3%~15.0%. This method is simple, fast and credible, can be applied to simultaneous screening and determination of estrogens, progesterones, androgens, glucocorticoids and resorcylic acid lactones belonging to the illegal additive of hormones in cereal feeds.

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Determination of 41 hormones in cereal feeds by liquid chromatography-tandem mass spectrometry HOU Jianbo1,2, XIE Wen1,2*, CHEN Xiaomei1,2, XI Junyang3, QIAN Yan3, WANG Feng3, LIU Haishan1,2 2011, 29 (06):  535-542.  DOI: 10.3724/SP.J.1123.2011.00535 Abstract ( 2345 )   [Full Text(HTML)] () PDF (243KB) ( 663 )   A method was developed for the determination of 10 androgens, 11 progesterones, 10 glucocorticoids, 5 estrogens and 5 resorcylic acid lactones in cereal feeds by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Ethyl acetate was used to extract the sample, and the mixed QuEChERS sorbents were dispersed for purification. The extract was separated by a C18 column and detected in positive or negative multiple reaction monitoring (MRM) mode. With the optimal conditions, the linear ranges of 41 hormones were 5.0~200.0 μg/kg with the correlation coefficients above 0.99 and the limits of quantification (LOQs, S/N≥10) were 0.123~2.72 μg/kg. The method validation was carried out at three spiking levels, and the recoveries were 70.3%~118.1% for soybean meals with the relative standard deviations (RSDs) of 0.82%~19.5%, and 76.1%~122.8% for corn meals with the RSD of 1.3%~15.0%. This method is simple, fast and credible, can be applied to simultaneous screening and determination of estrogens, progesterones, androgens, glucocorticoids and resorcylic acid lactones belonging to the illegal additive of hormones in cereal feeds.

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Determination of polybrominated diphenyl ethers and dechloraneplus in fish and fish oil supplements by gel permeation chromatography coupled with gas chromatography-negative chemical ionization mass spectrometry SHI Zhixiong1, WANG Yifei1, FENG Jinfang1, HUANG Peili1, WU Yongning1,2* 2011, 29 (06):  543-548.  Abstract ( 2019 )   [Full Text(HTML)] () PDF (207KB) ( 640 )   Polybrominated diphenyl ethers (PBDEs) and dechlorane plus (DP) are two kinds of widely used organic flame retardants, and PBDE and DP residues have been found in both environment and biota. A method for the determination of 8 PBDEs and 2 DPs in fish and fish oil supplements was developed using auto gel permeation chromatography (GPC) coupled with gas chromatography-negative chemical ionization/mass spectrometry (GC-NCI/MS) in the selected ion-monitoring (SIM) mode on a 15 m capillary column. The sample added with BDE-77 and 13C12-BDE-209 as the internal standards was extracted using a Soxhlet extractor, and further purified by auto GPC and a multilayer silica gel column. The sample preparation procedure was optimized, and the characteristic ions and fragmentations of the analytes in NCI/MS were studied. The limits of detection (LODs, S/N=3) ranged from 2.2 to 39.8 ng/kg. The average recoveries were between 71.1% and 121.4% at two spiked levels of 2 and 20 ng/g for both BDE-209 and DP and 0.2 and 2 ng/g for others with the relative standard deviations between 2.96% and 13.31%. The developed method has been successfully applied in the determination of PBDEs and DPs in several fish and fish oil supplements samples. The total PBDEs found ranged from 2.18 to 15.93 ng/g, and DP was not found. This method was validated to be accurate and sensitive for the trace analysis of PBDEs and DPs in the samples with fat.

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Flash evaporation-gas chromatographic fingerprints with hierarchical cluster analysis for the determination of cigarette flavors JIANG Jian1, YANG Jun1, HUANG Fangfang1, XU Shiqiang1, WANG Xiaoqing2, ZHENG Xiao2, PAN Zaifa2, WANG Lili2* 2011, 29 (06):  549-553.  DOI: 10.3724/SP.J.1123.2011.00549 Abstract ( 2473 )   [Full Text(HTML)] () PDF (198KB) ( 556 )   A method of flash evaporation-gas chromatographic (FE-GC) fingerprints with hierarchical cluster analysis was established for the quality control of the cigarette flavor samples. An amount of 0.40 mg of the cigarette flavor sample was analyzed by FE-GC at optimized the flash evaporation temperature, 350 ℃. Good reproducibility for chromatograms was obtained with the relative standard deviations (RSDs) of the retention time less than 0.22%, and the relative peak area less than 9.37%. Compared with ultrasound-assisted liquid-liquid extraction-gas chromatography (ULLE-GC), FE-GC was proved to be more suitable for the analysis of cigarette flavor samples with various viscosity. The similarity correlation coefficients were above 0.998 for the 8 batches of cigarette flavor No.1184. Furthermore, these samples could be successfully distinguished from the ones mixed with other kinds of flavor components at the mixed levels of 10%~30% by hierarchical cluster analysis. It demonstrated that the method of FE-GC fingerprints with hierarchical cluster analysis is simple, rapid, accurate, and suitable for the quality control of cigarette flavors.

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Determination of three sweeteners in vinegars by solid phase extraction-high performance liquid chromatography/tandem mass spectrometry YIN Feng1*, DING Zhaowei1, CAO Xue1, GAO Jie1, JIANG Deming1, KUANG Denghui2, GU Yanping1, HE Guoliang1 2011, 29 (06):  554-557.  DOI: 10.3724/SP.J.1123.2011.00554 Abstract ( 2546 )   [Full Text(HTML)] () PDF (158KB) ( 591 )   A solid phase extraction-high performance liquid chromatography/electrospray ionization-tandem mass spectrometry (SPE-HPLC/ESI-MS/MS) method for the determination of 3 sweeteners (acesulfame (AK), sodium saccharin (SA), sodium cyclamate (SC)) in vinegars has been developed. The sample was diluted with acidic water, then purified and enriched with a weak anion exchange SPE column. The HPLC separation was performed on a Pursuit C18 column (150 mm×2.0 mm, 3 μm) by gradient elution with 10 mmol/L ammonium acetate containing 0.1%(v/v) ammonia water and acetonitrile as the mobile phases. The analytes were detected by ESI~-MS/MS in multiple reaction monitoring (MRM) mode to satisfy qualitative and quantitative detections. Good linearities (r2＞0.99) were obtained over the range of 0.01~0.50 mg/L. The limits of quantification (LOQs) for SA, AK and SC were 10, 5 and 5 μg/kg, respectively. The average recoveries ranged from 72.1% to 96.8% at the spiked levels of 0.01 and 0.1 mg/L with the relative standard deviations (RSDs) less than 15%. This method is accurate, highly sensitive for qualitative and quantitative analysis of the 3 sweeteners in vinegars.

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Simultaneous determination of eleven sex hormones in antler velvet health products by gas chromatography-tandem mass spectrometry LU Chunmei, WANG Mingtai *, MU Jun, LU Lijun, ZHOU Xiao 2011, 29 (06):  558-562.  DOI: 10.3724/SP.J.1123.2011.00558 Abstract ( 2467 )   [Full Text(HTML)] () PDF (197KB) ( 514 )   A method for the simultaneous determination of 11 sex hormones in antler velvet health products by gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed. The sex hormones in antler velvet were enriched and purified by solid phase extraction and derivatized with heptafluorobutyric acid anhydride (HFBA). A DB-5 column (30 m×0.25 mm, 0.25 μm) with nonlinear gradient program was used in GC separation. The sex hormones were determined in the multiple reaction monitoring mode. The method realized the complete separation of 11 sex hormones. The limits of detection of this method were from 1.0 to 5.0 μg/kg for the 11 sex hormones. The correlation coefficients were between 0.9916 and 0.9999. The recoveries were in the range of 67.4%~99.1% with relative standard deviations (RSDs) of 2.6%~13%. This method is accurate and reliable for the determination of the sex hormones in antler velvet health products.

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Determination of phthalic acid esters in soil by gas chromatography-tandem mass spectrometry LI Hong*, TIAN Fulin, REN Xuedong, WANG Xinrui 2011, 29 (06):  563-566.  DOI: 10.3724/SP.J.1123.2011.00563 Abstract ( 2195 )   [Full Text(HTML)] () PDF (138KB) ( 656 )   A method based on gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed for the determination of phthalic acid esters (PAEs) in soil. The soil sample was extracted by dichloromethane-acetone (1:1, v/v) with an ultrasonic instrument, and the extract was cleaned up with a Florisil column. The identification and quantification of the analytes were carried out in the multiple reaction monitoring (MRM) mode after the GC separation on an HP-5MS column (30 m×0.25 mm×0.25 μm). The eight point calibration curves showed a good linearity for all the congeners (0.9973~0.9976). The limits of detection (LODs) ranged from 0.1 to 0.5 μg/kg. The relative standard deviations(RSDs) were not more than 14.3% and the spiked recoveries were in the range of 72.9%~106.2%. The developed analytical method is rapid and accurate, and suitable for the determination of PAEs in soil.

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Quantitative analysis of hinokiol from cell suspension cultures of Cephalotaxus fortunei XU Xiaohui1,2, ZHANG Wei1,3*, YAO Changhong1,2, CAO Xupeng1, XUE Song1* 2011, 29 (06):  567-570.  DOI: 10.3724/SP.J.1123.2011.00567 Abstract ( 1921 )   [Full Text(HTML)] () PDF (166KB) ( 445 )   A high performance liquid chromatography (HPLC) method was developed for the separation of secondary metabolites and quantitative analysis of hinokiol from cell suspension cultures of Cephalotaxus fortunei. The samples were prepared by extraction using methanol followed by partitioning between ammonium hydroxide and chloroform. The HPLC separation was achieved on an Apollo C18 column (250 mm×4.6 mm, 5 μm) with gradient elution using methanol and water at 1 mL/min and 30 ℃. The detection was carried out at 290 nm. A good linear correlation between the hinokiol peak area and mass concentration was observed over the mass concentration range of 0.0125~0.2 g/L. The proposed method was applied to the determination of hinokiol in the actual samples with recoveries of 87.2%~94.7% and with the relative standard deviations of 0.9%~4.2%. This method is reliable and reproducible and is suitable for the analysis of hinokiol in plant cell cultures.