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Chinese Journal of Chromatography
2014, Vol. 32, No. 5
Online: 08 May 2014

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Application of chromatographic techniques in separation and analysis of bioactive natural products 2014, 32 (5):  445-446.  DOI: 10.3724/SP.J.1123.2014.03038 Abstract ( 459 )   [Full Text(HTML)] () PDF (750KB) ( 254 )

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Preparation and application of mixed-mode capillary polymer monolithic column DOU Abo, ZOU Cunjie, SHAN Yuanhong, SHI Xianzhe, XU Guowang 2014, 32 (5):  447-451.  DOI: 10.3724/SP.J.1123.2013.12040 Abstract ( 848 )   [Full Text(HTML)] () PDF (897KB) ( 203 )   Based on the diversity of the retention mechanism, mixed-mode capillary monolithic columns have broad application prospect. In this work, a novel capillary polymer monolithic column was prepared with [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SPE) as monomer, ethylene dimethacrylate (EDMA) as crosslinking agent, azobisisobutyronitrile (AIBN) as initiator and butylalcohol/1,4-butanediol/water as ternary porogens. Under the optimized reaction conditions including the proportion of monomer and porogens, amount of initiator, reaction temperature and polymerization time, the monolithic column showed good mechanical strength up to 10 MPa, high permeability of 2.17×10-14 m2 and good repeatability. The peak area RSDs of column-to-column and batch-to-batch reproducibility were 1.0% and 4.6%, respectively. Finally, the capillary monolithic column was evaluated with polar and non-polar test mixtures. It showed hydrophilic interaction under high organic phase while hydrophobic interaction under low organic phase, indicating it a mixed-mode monolithic column.

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Preparation of a new immobilized cellulose-based chiral stationary phase and its enantioseparation behaviors TU Hongsheng, FAN Jun, TAN Yi, LIN Chun, HUA Jiangying, ZHANG Weiguang 2014, 32 (5):  452-457.  DOI: 10.3724/SP.J.1123.2014.01022 Abstract ( 836 )   [Full Text(HTML)] () PDF (927KB) ( 314 )   The immobilized polysaccharide-based chiral stationary phase has attracted considerable attention over the past decades due to its high chemical stability, good solvent resistance, great enantioseparation ability, etc. In this study, a new immobilized cellulose chiral stationary phase (denoted as ImCel) was prepared through the Staudinger reaction of 6-azido-6-deoxy-cellulose-3,5-dichlorophenylcarbamate and aminopropyl silica gel. The enantioseparation performance of the ImCel for 20 pairs of chiral analytes and the effect of non-standard solvents have been investigated by high performance liquid chromatography. Baseline separations of 17 pairs of enantiomers were achieved on the ImCel. The separation ability of the ImCel in the normal mode was much better than in reversed mode. In addition, the ImCel showed good chemical stability in the non-standard mobile phase due to the covalent bonds between the cellulose chiral selectors and silica support. Moreover, it exhibited complementarity with another immobilized-cellulose chiral stationary phase containing 3,5-dimethylphenylcarbamate groups for the separation of a series of 9-fluorenylmethyloxycarbonyl (fmoc)-derived amino acids. The reversal of enantiomer elution order induced by the difference of the substituents in chiral stationary phase was observed under the same chromatographic conditions. In brief, a new immobilized cellulose chiral stationary phase with high stability and good separation performance was developed in this work.

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Preparation and application of di(2-propylheptyl) phthalate molecularly imprinted solid-phase extraction sorbent WEI Shoulian, GUO Xiaojun, YAN Zijun, LIU Yong, WANG Hongwu 2014, 32 (5):  458-463.  DOI: 10.3724/SP.J.1123.2014.01007 Abstract ( 1110 )   [Full Text(HTML)] () PDF (942KB) ( 407 )   The molecular imprinted polymer (MIP) with high selectivity to di(2-propylheptyl) phthalate (DPHP) was synthesized by precipitation polymerization with dioctyl phthalate (DOP) as dummy template, methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EDMA) as cross-linker. The binding ability of the template and functional monomer was investigated by UV spectrometry. Compared with the functional monomer acrylic acid (AA), MAA showed stronger binding capacity to DOP and the best combination mole ratio of 6:1. The selective adsorption performance of MIP for DOP, DPHP, dimethyl phthalate (DMP) and dibutyl phthalate (DBP) was investigated using the prepared MIP as high performance liquid chromatographic column packing. It was found that the prepared MIP showed higher retention ability and selectivity for DPHP. Using the prepared MIP as a solid-phase extraction (SPE) sorbent (MISPE), the effects of the type and amount of washing solvent and elution solvents on the recovery of DPHP were investigated. After optimization of MISPE profile, the DPHP extraction recovery of 96.8% was obtained when the following procedures were applied to MISPE cartridge: conditioning with 2 mL methanol, loading with 1 mL methanol, washing with 1 mL methanol-water (1:9, v/v), eluting with 5 mL methanol-acetic acid (9:1, v/v). The recovery of DPHP on non-imprinted polymer (NIP) cartridge was only 52.9%. The developed MISPE-HPLC method was applied to determine the concentrations of DPHP in rabbit serum at different time points after oral administration. It was found that the maximal concentration (cmax) and time (tmax) were 5.88 μg/mL and 4 h, respectively. The recoveries of spiked DPHP in rabbit serum ranged from 90.0% to 92.0% with the relative standard deviations less than 5%。

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Application of metabolomics in treating polycystic ovary syndrome with berberine based on ultra high performance liquid chromatography-mass spectrometry LI Yanjie, ZHANG Chunlan, ZHANG Han, ZHAO Xinjie, HOU Lihui, XU Guowang 2014, 32 (5):  464-471.  DOI: 10.3724/SP.J.1123.2014.01006 Abstract ( 893 )   [Full Text(HTML)] () PDF (1156KB) ( 499 )   Polycystic ovary syndrome (PCOS) is a complex, heterogeneous disorder, which seriously impacts the health of reproductive age women. Thus reasonable individual-based treatment is important. In this study, the serum samples of 15 overweight PCOS patients before and after treatment with berberine for three months were collected for clinic biochemical test and metabolomic research. Metabolomic profiling based on ultra high performance liquid chromatography (UHPLC) coupled with quadrupole time-of-flight mass spectrometry (q-TOF MS) was used to investigate metabolic changes of PCOS. Compared with before treatment, the patients after berberine treatment can be separated into distinct clusters as displayed by the orthogonal signal correction partial least-squares discriminant analysis (OSC-PLS-DA) score plot with model parameter: R2Y=0.892, Q2(cum)=0.577, which indicated changes in metabolites after berberine treatment. The differential metabolites related to berberine treatment were selected when their variable importance values were more than 1, and p<0.05 with nonparametric test. These differential metabolites were all involved in lipids metabolism, including phosphatidylcholines, sphingomyelin, stearic acid and erucamide. The pharmacological results and metabolomic data revealed that berberine can strengthen the sensitivity of insulin and rectify the dyslipidemia of overweight PCOS patients. This study also illustrates that the LC-MS based metabolomic method is helpful for evaluating the treatment of traditional Chinese medicines.

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Simultaneous determination of sixteen perfluorinated organic compounds in surface water by solid phase extraction and ultra performance liquid chromatography with electrospray ionization tandem mass spectrometry ZHANG Ming, TANG Fangliang, YU Yayun, CHEN Feng, XU Jianfen, YE Yonggen 2014, 32 (5):  472-476.  DOI: 10.3724/SP.J.1123.2014.01042 Abstract ( 658 )   [Full Text(HTML)] () PDF (884KB) ( 405 )   A high-throughput detection method has been developed for the determination of sixteen perfluorinated organic compounds (PFCs) in surface water by solid phase extraction-ultra performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (SPE-UPLC-ESI-MS/MS). The water samples were concentrated and purified through WAX solid phase extraction cartridges. The UPLC separation was performed on an ACQUITY UPLCTM BEH C18 column utilizing a gradient elution program of methanol (containing 2 mmol/L ammonium acetate) and water (containing 2 mmol/L ammonium acetate) as the mobile phases at a flow rate of 0.4 mL/min. The MS/MS detection was performed under negative electrospray ionization (ESI-) in multiple reaction monitoring (MRM) mode. Good linearities were observed in the range of 0.5-100 μg/L or 1.0-100 μg/L with correlation coefficients from 0.9987 to 0.9999. The limits of detection (LODs) for the sixteen perfluorinated organic compounds were in the range of 0.06-0.46 ng/L. The recoveries ranged from 67.6% to 103% with the relative standard deviations between 2.94% and 12.0%. This method was characterized by high sensitivity and precision, extensive range and high speed, and can be applied for the analysis of PFC contaminants in surface water.

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Screening and confirmation of 24 hormones in cosmetics by ultra high performance liquid chromatography-linear ion trap/orbitrap high resolution mass spectrometry LI Zhaoyong, WANG Fengmei, NIU Zengyuan, LUO Xin, ZHANG Gang, CHEN Junhui 2014, 32 (5):  477-484.  DOI: 10.3724/SP.J.1123.2013.12004 Abstract ( 835 )   [Full Text(HTML)] () PDF (964KB) ( 363 )   A method of ultra high performance liquid chromatography-linear ion trap/orbitrap high resolution mass spectrometry (UPLC-LTQ/Orbitrap MS) was established to screen and confirm 24 hormones in cosmetics. Various cosmetic samples were extracted with methanol. The extract was loaded onto a Waters ACQUITY UPLC BEH C18 column (50 mm×2.1 mm, 1.7 μm) using a gradient elution of acetonitrile/water containing 0.1%(v/v) formic acid for the separation. The accurate mass of quasi-molecular ion was acquired by full scanning of electrostatic field orbitrap. The rapid screening was carried out by the accurate mass of quasi-molecular ion. The confirmation analysis for targeted compounds was performed with the retention time and qualitative fragments obtained by data dependent scan mode. Under the optimal conditions, the 24 hormones were routinely detected with mass accuracy error below 3×10-6(3 ppm), and good linearities were obtained in their respective linear ranges with correlation coefficients higher than 0.99. The LODs (S/N=3) of the 24 compounds were ≤10 μg/kg, which can meet the requirements for the actual screening of cosmetic samples. The developed method was applied to screen the hormones in 50 cosmetic samples. The results demonstrate that the method is a useful tool for the rapid screening and identification of the hormones in cosmetics.

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Determination of 18 pesticide residues in red wine by ultra high performance liquid chromatography-high resolution mass spectrometry with isotope dilution technique CHEN Dawei, LÝ Bing, DING Hao, ZOU Jianhong, YANG Xin, ZHAO Yunfeng, MIAO Hong 2014, 32 (5):  485-492.  DOI: 10.3724/SP.J.1123.2014.01012 Abstract ( 927 )   [Full Text(HTML)] () PDF (1447KB) ( 400 )   A method for the simultaneous determination of 18 pesticide residues in red wine was developed using ultra high performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) with isotope dilution technique. The red wine samples were extracted with acetonitrile, and the extracts were cleaned up with dispersive solid phase extraction (d-SPE) using the mixture of N-propyl ethylene diamine (PSA) and C18 powder as sorbent. The extracted components were separated on a BEH C18 column by gradient elution. The qualitative and quantitative analyses were operated under full scan/data dependent MS/MS (ddms2) and targeted selective ion monitoring (tSIM) by high resolution mass spectrometry, respectively. Carbendazim-D4, chlorpyrifos-D10, imidacloprid-D4, methoxyfenozide-D9, pyrimethanil-D5 and tebuconazole-D6 were used as the internal standards to reduce the matrix effects. The response of each pesticide showed a good linearity in the range of 0.5-50 μg/kg with the correlation coefficient more than 0.999. The limits of detection and quantification for the 18 pesticides in the spiked blank red wine were 0.5 μg/kg and 1.0 μg/kg, respectively. The recovery results with spiked blank red wine samples at the levels of 1 to 40 μg/kg were satisfactory with average recoveries of 85.4%-117.9% and the RSDs of 0.5%-6.1%. The method was applied for the determination of the red wine real samples from the market. Carbendazim, imidacloprid, pyrimethanil, tebuconazole and triadimenol were detected in the samples. The results show that the method is suitable for the rapid screening and quantitative analysis of pesticide residues in red wine.

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Determination of three exogenous plant hormone residues in bean sprout by high performance liquid chromatography-quadrupole-time of flight mass spectrometry XIE Hanbing, ZHOU Mingying, ZHAO Haifeng, WANG Yigang, JIANG Wanfeng, ZHAO Shan 2014, 32 (5):  493-498.  DOI: 10.3724/SP.J.1123.2013.12029 Abstract ( 824 )   [Full Text(HTML)] () PDF (999KB) ( 347 )   This study was aimed to the establishment of an analytical method for the determination of three exogenous plant hormone residues in bean sprout by high performance liquid chromatography-quadrupole-time of flight mass spectrometry (HPLC-Q-TOF-MS). The target compounds were gibberellins, 6-benzylaminopurine and parachlorophenoxyacetic acid. The QuEChERS (quick, easy, cheap, effective, rugged, and safe) method was used for sample preparation. The analytes were extracted with a solution containing 1% (v/v, if not specified) acetic, 50% ethanol, 49% acetonitrile, and cleaned-up by dispersive solid-phase extraction with diatomite dispersant, then degreased by hexane. The three target compounds were separated on an Eclipse Plus C18 column (100 mm×3.0 mm, 1.8 μm) with mobile phases A (water containing 0.1% formic acid) and B (methanol) by gradient elution within 15 min, and detected under negative electrospray ionization (ESI) mode. The quantitative analysis was carried out by extracting the peak area with accurate mass. The confirmatory analysis of the target compounds was performed with the qualitative fragments. The results showed that the limits of quantification (LOQs, S/N=10) for the three target compounds were from 5.0 μg/kg to 10 μg/kg. The respective mean recoveries were found to be in the range of 79.1%-96.1%, and the RSDs were 5.7%-10.4%. It was applicable to the analysis of the three exogenous plant hormones in bean sprout samples. This method is simple, fast and efficient.

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Determination of N-methyl carbamate pesticides in diet samples by high performance liquid chromatography-linear ion trap mass spectrometry with gel permeation chromatography cleanup YANG Xin, LI Peng, MIAO Hong, ZHAO Yunfeng, WU Yongning 2014, 32 (5):  499-505.  DOI: 10.3724/SP.J.1123.2013.12041 Abstract ( 556 )   [Full Text(HTML)] () PDF (944KB) ( 184 )   A method for the determination of N-methyl carbamate (NMC) pesticides in diet samples was developed by high performance liquid chromatography-linear ion trap mass spectrometry (HPLC-LIT-MS). The samples with the isotope internal standard were ultrasonically extracted with acetonitrile saturated with cyclohexane, and then cleaned-up by passing through gel permeation chromatographic (GPC) column. The LC separation was performed on a CAPCELL PAK CR column (100 mm×2.1 mm, 5 μm; SCX-C18 (1:4)) using acetonitrile and 5 mmol/L ammonium formate/0.1% (v/v) formic acid aqueous solution as mobile phases (gradient elution) at a flow rate of 0.2 mL/min. The ionization of the analytes was performed by positive electrospray mode. Selective reaction monitoring (SRM) was used for the monitoring of MS3 transitions for each compound. The internal standard was used for quantitation. The average recoveries were in the range of 60.4%-114%, and the relative standard deviations (RSDs) were all not more than 16.2%. The limits of detection (LODs) were 0.001-0.010 mg/kg. The method was successfully applied to the determination of 15 compounds of interest in nine foodstuffs from the fourth Chinese Total Diet Study (TDS) performed in 2007, and aldicarb and carbofuran were found in several samples.

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Fast analysis of indole alkaloids from Evodiae fructus by supercritical fluid chromatography LI Zhenyu, FU Qing, LI Kuiyong, LIANG Tu, JIN Yu 2014, 32 (5):  506-512.  DOI: 10.3724/SP.J.1123.2013.12035 Abstract ( 853 )   [Full Text(HTML)] () PDF (979KB) ( 283 )   A fast chromatographic separation of indole alkaloids from Evodiae fructus was developed by supercritical fluid chromatography (SFC). The initial screening of four stationary phases was investigated with a standard mixture of evodiamine and rutaecarpine, and a complex sample of indole alkaloids prepared from Evodiae fructus as probes. Later, the effects of chromatographic parameters on separation were studied including injection volume, organic modifier, additive, temperature and back pressure. The injection volume had significant impact on the peak shape. With the additives in the mobile phase, slight changes in peak shape and retention time were observed in separation. Variation in organic modifier led to dramatic change in chromatographic behavior. Both decreased temperature and increased back pressure shortened the retention time. Finally, a fast analytical method using SFC, on a Waters ACQUITY UPC2 BEH column, methanol as modifier, under 35 ℃ and 2.07×107 Pa, was developed to separate a complex sample of indole alkaloids in less than 15 min. Another rapid approach for the separation of a complex sample of indole alkaloids was developed by using ultra-high performance liquid chromatography (UHPLC). As a result, SFC can be used in the separation of natural products, giving high performance, good resolution and fast analysis speed. The difference in selectivity with UHPLC can be used to the development of natural product separation.

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Determination of biurea in flour and its products by liquid chromatography-tandem mass spectrometry WANG Ya, WANG Junsu, XIANG Lu, XI Cunxian, CHEN Dongdong, PENG Tao, WANG Guomin, MU Zhaode 2014, 32 (5):  513-518.  DOI: 10.3724/SP.J.1123.2013.12023 Abstract ( 737 )   [Full Text(HTML)] () PDF (887KB) ( 401 )   A novel method was established for the determination and identification of biurea in flour and its products using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The biurea was extracted with water and oxidized to azodicarbonamide by potassium permanganate. The azodicarbonamide was then derivatized using sodium p-toluene sulfinate solution. The separation was performed on a Shimpak XR-ODSⅡ column (150 mm×2.0 mm, 2.2 μm) using the mobile phase composed of acetonitrile and 2 mmol/L ammonium acetate aqueous solution (containing 0.2% (v/v) formic acid) with a gradient elution program. Tandem mass spectrometric detection was performed in multiple reaction monitoring (MRM) scan mode with a positive electrospray ionization (ESI+) source. The method used stable isotope internal standard quantitation. The calibration curve showed good linearity over the range of 1-20000 μg/kg(R2=0.9999). The limit of quantification was 5 μg/kg for biurea spiked in flour and its products. At the spiking levels of 5.0, 10.0 and 50.0 μg/kg in different matrices, the average recovery of biurea was 78.3%-108.0% with the relative standard deviations (RSDs)≤5.73%. The method developed is novel, reliable and sensitive with wide linear range, and can be used to determine the biurea in flour and its products.

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Determination of cefalonium residue in milk by high performance liquid chromatography-tandem mass spectrometry LI Shuaipeng, GUO Chunna, MENG Lei, HUANG Xianhui 2014, 32 (5):  519-523.  DOI: 10.3724/SP.J.1123.2013.12028 Abstract ( 814 )   [Full Text(HTML)] () PDF (910KB) ( 332 )   An analytical method was developed for the determination of cefalonium in milk by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). A total of 1 g milk was deproteinized by acetonitrile. The supernatant was transferred into a test tube to be blown dry with N2 at 37 ℃. Then the residue was dissolved with methanol-0.1% formic acid in water (3:7, v/v). The sample was determined by HPLC-MS/MS after the purification. The chromatographic separation was achieved on a C18 column using 0.1% formic acid in water and acetonitrile as mobile phases with gradient elution. Qualitative and quantitative analyses were achieved by HPLC-MS/MS under positive ionization and multiple reaction monitoring (MRM) mode. Matrix-matched calibration curve was used for the quantification. Good correlation coefficients were obtained (r>0.999) in the mass concentration range of 2-200 μg/L. The limit of detection (LOD, S/N≥3) was 0.5 μg/kg in milk, and the limit of quantification (LOQ, S/N≥10) was 2 μg/kg. The mean recoveries at the four levels of LOQ, 1/2MRL (maximum residue level), MRL, 2MRL were between 78.5% and 86.2%, with the intra-day relative standard deviations (RSDs)of 1.5% to 6.2% and inter-day RSDs of 2.9% to 5.6%. In conclusion, the established method can be applied for the determination of cefalonium residue in milk.

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Determination of sulfonamide potentiators in animal origin foods by ultra performance liquid chromatography-tandem mass spectrometry GAO Yangyang, ZHANG Zhaohui, LIU Xin, LU Xiaoyu, YAN Hua, HE Yue, YANG Dajin, YUN Huan 2014, 32 (5):  524-528.  DOI: 10.3724/SP.J.1123.2014.01008 Abstract ( 672 )   [Full Text(HTML)] () PDF (931KB) ( 250 )   A method for the determination of sulfonamide potentiators, trimethoprim (TMP), diaveridine (DVD) and ormetoprin (OMP), in different animal origin food matrices (including chicken muscle, fish muscle, chicken liver, egg and milk) has been developed by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The sample was extracted by formic acid-acetonitrile (1:9, v/v), cleaned-up by hexane, separated on an Acquity UPLC BEH C18 column (50 mm×2.1 mm, 1.7 μm) with gradient elution. The determination was carried out with electrospray ion source under the positive mode and multiple reaction monitoring (MRM) mode. The extraction recoveries of three extraction solvents were observed. The purification condition and concentration condition were optimized. In addition, the mobile phase, column temperature and solid phase extraction column were studied. The calibration curves showed a good linearity in the range of 1.25-30.0 μg/L, and the correlation coefficients (r) were higher than 0.99. The limits of quantification (LOQ, S/N=10) of the three potentiators were 5.0 μg/kg. At the spiked levels of 5.0, 10.0 and 20.0 μg/kg, the recoveries of the three potentiators were ranged from 61.2% to 108.5%, and the relative standard deviations (RSD, n=6) ranged from 1.1% to 9.8%. The results indicate that the method is simple, rapid, sensitive and suitable for the qualitative and quantitative analysis of the three potentiators in multiple matrices.

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Determination of bisphenol A, tetrabromobisphenol A and alkylphenols in water samples of sewage treatment plant using liquid chromatography-tandem mass spectrometry DING Jie, ZHANG Shenghu, LIU Jining, ZHOU Linjun, CHEN Guosong, SHI Lili 2014, 32 (5):  529-534.  DOI: 10.3724/SP.J.1123.2013.12043 Abstract ( 693 )   [Full Text(HTML)] () PDF (916KB) ( 392 )   Bisphenol A, tetrabromobisphenol A and alkylphenols have received much attention in recent years because of their endocrine disrupting effects to aquatic ecosystem. The fate of these compounds in sewage treatment plant which is important to deal with this kind of compounds has significance on the study of exposure levels of the target compounds in the environment, and the development of analytical method is the basis on the above study. An analytical method based on liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) with negative ionization mode has been developed for measuring bisphenol A, tetrabromobisphenol A and six alkylphenols in raw and treated sewage samples. The target compounds were separated on a ZORBAX Eclipse Plus C18 column (150 mm×2.1 mm, 3.5 μm) with mobile phases of acetonitril and 0.02% (v/v) ammonia. Analyte confirmations were performed under multiple reaction monitoring (MRM) mode and the eight compounds were separated within 11 min. The calibration curves were linear in the range of 1-100 μg/L (R2≥0.998). The quantification limits of the eight compounds were 2.0-20 ng/L. The recovery experiments were performed with samples spiked at the levels of 0.2, 2 and 20 μg/L, and the recoveries for the target compounds were in the range of 64.3%-118.0%, 65.9%-100.5% and 70.3%-102.7% (RSD<7.1%, n=3), respectively. Based on the analytical method, the raw and treated sewage samples from an industrial park of Jiangsu Province were analyzed. Five compounds were detected in the water outlet in the range of 11.9-3015.3 ng/L. It shows that the method is simple, selective, sensitive and can be used to analyze the water samples of sewage treatment plant containing alkylphenols.

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Analysis of picric acid and picramic acid in water samples by ultra performance hydrophilic interaction chromatography-tandem mass spectrometry QIAN Feizhong, ZHU Libo, XU Nengbin, FENG Jiayong, HONG Zhengfang, XU Lihong, CHEN Zhongquan, WANG Shengle 2014, 32 (5):  535-538.  DOI: 10.3724/SP.J.1123.2013.11037 Abstract ( 1096 )   [Full Text(HTML)] () PDF (891KB) ( 215 )   An ultra performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method was developed for the determination of picric acid and its reductive transformation product picramic acid in aqueous samples. A hydrophilic interaction liquid chromatography (HILIC) column (Acquity UPLC BEH HILIC; 100 mm×2.1 mm, 1.7 μm) was used for the separation. Surface water samples could be injected into the UPLC system just after being filtered through a 0.2 μm membrane. The satisfactory recoveries of picric acid and picramic acid were in the range of 89%-107%. Waste water samples were purified by solid phase extraction (SPE), and then were analyzed. The recoveries of picric acid and picramic acid in waste water were 72%-101%. The reproducibility of the method was good with the RSDs of 4.9%-14.7%. The limits of detection (LODs) of picric acid and picramic acid were 0.1 μg/L and 0.3 μg/L, respectively. This proposed method is rapid, highly specific and suitable for the confirmation and quantitative determination of picric acid and picramic acid in surface water and waste water.

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Determination of activity of transglycosidase in diastatic enzyme by high performance liquid chromatography LI Shuanghua, FENG Si, CHEN Yinjia, LI Tong 2014, 32 (5):  539-542.  DOI: 10.3724/SP.J.1123.2013.12031 Abstract ( 678 )   [Full Text(HTML)] () PDF (879KB) ( 307 )   An analytical method for the determination of the activity of transglycosidase in diastatic enzyme by high performance liquid chromatography (HPLC) was established. Taken as the substrate, maltose was transformed into trisaccharide by transglycosidase in a 37 ℃ water bath and acetic acid buffer solution (pH=4.8) with acarbose as transglycosidase inhibitor. The transformation of the trisaccharide was detected on a SUGAR SH1011 column (300 mm×8.0 mm, 6 μm) with 0.01 mol/L sulfuric acid solution as mobile phase at a flow rate of 0.6 mL/min and a differential refractive index detector (RID), in order that the activity of transglycosidase can be measured indirectly. The conditions such as the chromatographic conditions, the concentration of substrate, the usage of inhibitor, and the incubation time were investigated. Under the optimized separation conditions, the calibration curve of the trisaccharide showed good linearity within the mass concentrations of 0.1-10 g/L (r=0.9998). The limit of detection and the limit of quantitation for transglycosidase activity were 0.013 U and 0.043 U, respectively. The relative standard deviation was 0.63% for six parallel tests. The activities of transglycosidase from different batches of diastatic enzyme were also determined with good result. The method can be applied to determine the activity of transglycosidase in the diastatic enzyme of the producers’ raw materials with the advantages of convenience, simplicity and stability.

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Isolation and preparation of an imidazole alkaloid from radix of Aconitum pendulum Busch by semi-preparative high-speed counter-current chromatography LIU Yongling, CHEN Tao, CHEN Chen, ZOU Denglang, LI Yulin 2014, 32 (5):  543-546.  DOI: 10.3724/SP.J.1123.2013.12007 Abstract ( 710 )   [Full Text(HTML)] () PDF (846KB) ( 290 )   Aconitum pendulum Busch is rich C19 diterpenoid alkaloids, but there is no report of imidazole alkaloid in Aconitum pendulum Busch. In this study, an imidazole alkaloid named 1H-imidazole-2-carboxylic acid, butyl ester (ICABE) was successfully separated from Aconitum pendulum Busch with semi-preparative high-speed counter-current chromatography (HSCCC). The partition coefficient was measured by HPLC to select the solvent systems for ICABE separation by HSCCC. The separation was performed with a two-phase solvent system composed of n-hexane-chloroform-ethanol-water (10:1:13:2, v/v/v/v). The upper phase was used as the stationary phase and the lower phase as the mobile phase. It was operated at a flow rate of 1.8 mL/min. The apparatus was rotated at 850 r/min, and the detection wavelength was set at 230 nm. Under the selected conditions, a high efficiency separation of HSCCC was achieved, and 7.5 mg of ICABE was obtained from 100 mg of the crude sample of Aconitum pendulum in one-step separation within 350 min. The HPLC analysis showed that the purity of the compound was over 98%. The chemical structure was confirmed by UV, 1H-NMR and 13C-NMR. The established method is simple, highly efficient and suitable for large scale separation of ICABE from radix of Aconitum pendulum Busch.

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Pyrolysis of the Lysimachia foenum-graecum Hance extract by online pyrolysis-gas chromatography-mass spectrometry YANG Yekun, MIAO Enming, GENG Yongqin, Wei Yuling, XU Jicang, LI Xuemei, DING Zhongtao, ZHOU Jun 2014, 32 (5):  547-552.  DOI: 10.3724/SP.J.1123.2013.11049 Abstract ( 1116 )   [Full Text(HTML)] () PDF (898KB) ( 355 )   In order to study the pyrolytic properties of Lysimachia foenum-graecum Hance extract, it was pyrolysed and detected by online pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). The pyrolytic experimental conditions were designed to simulate the real combustion conditions inside a burning cigarette. The sample was heated at 30 ℃/s from 300 to 900 ℃ (held for 5 s) under the flow of 9% oxygen in nitrogen. The pyrolytic components and volatile components were compared. The results showed that 64 pyrolytic components were detected, with 88.27% of the total peak area, including linoleic acid ethyl ester (10.33%), hexadecanoic acid, ethyl ester (9.12%), 9,12,15-octadecatrienoic acid, (Z,Z,Z)-(8.03%), 2-furancarboxaldehyde, 5-(hydroxymethyl)-(6.02%), neophytadiene (5.12%), heptadecanoic acid, ethyl ester(4.50%), acetic acid, phenyl ester(3.51%), 5-methoxy-2,2-di-methylindan-1-one (2.73%). The number of pyrolytic components was more than that of the volatile components, and 20 components were identified in both pyrolytic components and volatile components, including higher fatty acids and their esters, neophytadiene, 2-furancarboxaldehyde, 5-(hydroxymethyl)-, and 2(5H)-furanone, 3-hydroxy-4,5-dimethyl-. The on-line pyrolysis was similar to the real cigarette combustion conditions. The method is a simple, rapid and good qualitative method for the pyrolysis.

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Simultaneous determination of seven residual solvents in bovis calculus artifactus by headspace gas chromatography CHI Shuyao, WU Dike, SUN Jinhong, YE Ruhan, WANG Xiaoyan 2014, 32 (5):  553-557.  DOI: 10.3724/SP.J.1123.2014.01013 Abstract ( 953 )   [Full Text(HTML)] () PDF (908KB) ( 364 )   A headspace gas chromatography (HS-GC) method was developed for the simultaneous determination of seven residual solvents (petroleum ether (60-90 ℃), acetone, ethyl acetate, methanol, methylene chloride, ethanol and butyl acetate) in bovis calculus artifactus. The DB-WAX capillary column and flame ionization detector (FID) were used for the separation and detection of the residual solvents, and the internal standard method was used for the quantification. The chromatographic conditions, such as equilibrium temperature and equilibrium time, were optimized. Under the optimized conditions, all of the seven residual solvents showed good linear relationships with good correlation coefficients (not less than 0.9993) in the prescribed concentration range. At three spiked levels, the recoveries for the seven residual solvents were 94.7%-105.2% with the relative standard deviations (RSDs) less than 3.5%. The limits of detection (LODs) of the method were 0.43-5.23 mg/L, and the limits of quantification (LOQs) were 1.25-16.67 mg/L. The method is simple, rapid, sensitive and accurate, and is suitable for the simultaneous determination of the seven residual solvents in bovis calculus artifactus.