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Chinese Journal of Chromatography
2011, Vol. 29, No. 11
Online: 28 November 2011

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Current highlights of researches on chromatography and capillary electrophoresis XU Xu 2011, 29 (11):  1047-1048.  DOI: 10.3724/SP.J.1123.2011.01047 Abstract ( 1335 )   [Full Text(HTML)] () PDF (86KB) ( 590 )

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Evaluation of the effect of the traditional Chinese medicine Tongxinluo or ginseng on excess fatigue rats studied by metabonomics approach based on liquid chromatography-mass spectrometry DAI Weidong1, ZHANG Fengxia1, JIA Zhenhua2, WEI Cong2, GAO Peng1, LU Xin1, WU Yiling2*, XU Guowang1* 2011, 29 (11):  1049-1054.  DOI: 10.3724/SP.J.1123.2011.01049 Abstract ( 2411 )   [Full Text(HTML)] () PDF (312KB) ( 593 )   Excess fatigue is a pathological state of continuing accumulation of fatigue, which may cause the deterioration of body health, occurrence of diseases, and even lead to death. A metabonomics study was performed on the excess fatigue rats treated with traditional Chinese medicine Tongxinluo or ginseng based on ultra fast liquid chromatography coupled with ion trap-time of flight mass spectrometry (UFLC-IT-TOF-MS). The plasma metabolic profiling data of the control rats, excess fatigue rats, and excess fatigue rats treated with Tongxinluo or ginseng were acquired. The orthogonal partial least squares analysis (OPLS) was applied for the multivariate statistics and the discovery of important differential metabolites distinguishing the excess fatigue rats treated with Tongxinluo or ginseng from the control rats and excess fatigue rats. The results showed tryptophan, bile acid, lysophosphatidylcholine metabolism were disturbed in the excess fatigue rats. The metabolic pattern including the related metabolic pathways of the rats, being treated with Tongxinluo or ginseng, was adjusted towards the normal state.

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Determination of 6 antiestrogens in fish tissues by ultra performance liquid chromatography-tandem mass spectrometry XIAO Shensheng1, YANG Yi2, ZHANG Jing2, WU Yongning1,3*, SHAO Bing2 2011, 29 (11):  1055-1061.  DOI: 10.3724/SP.J.1123.2011.01055 Abstract ( 1935 )   [Full Text(HTML)] () PDF (327KB) ( 585 )   A comprehensive analytical method based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been developed for the simultaneous determination of 6 antiestrogens (toremifene, clomiphene, tamoxifen, raloxifene, anastrozole and letrozole) in fish muscle and liver. The multi-reaction monitoring mode was employed for the determination. The homogeneous fish tissue samples were ultrasonically extracted with acetonitrile, and then the supernatants were diluted by water. The target compounds were concentrated and purified by a mixed-mode cationic-exchanger (MCX) cartridge, and then separated on an ACQUITY UPLCTM BEH C18 column (100 mm×2.1 mm, 1.7 μm) using a binary mobile phase gradient with water containing 0.1% formic acid and acetonitrile. The limits of quantification (LOQ, S/N=10) of the 6 antiestrogens were 0.1~0.3 μg/kg in muscle and liver samples. The average recoveries of target compounds (spiked at four concentration levels) based on internal standard calibration were in the range of 84.9%~112.2% with the relative standard deviations of 0.9%~14.3%. This method can be applied to the trace analysis of target drugs in fish muscle and liver samples.

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Determination of commonly abused dyes in food by liquid chromatography-tandem mass spectrometry YI Xionghai*, DENG Xiaojun, YANG Huiqin, GUO Dehua, ZHU Jian 2011, 29 (11):  1062-1069.  DOI: 10.3724/SP.J.1123.2011.01062 Abstract ( 1959 )   [Full Text(HTML)] () PDF (314KB) ( 699 )   A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of commonly abused dyes in candy, sirup, liquid milk and fruit juice. The test sample was dissolved and diluted with water, then cleaned up by polyamide solid phase extraction. The LC separation was performed on an Agilent XDB-C18 column with 20 mmol/L ammonium acetate solution and acetonitrile as the mobile phase in a gradient elution mode. The dyes were determined by MS/MS in negative electrospray ionization mode, and quantified by matrix-matched external standard method. The calibration curves showed good linearity in the range of 0.5~50 mg/L with the correlation coefficients (r) greater than 0.99. The limits of quantitation (S/N>10) were 0.5 mg/kg, and the limits of detection (S/N>3) were 0.1 mg/kg. The recoveries of dyes in food samples at the three spiked levels of 0.5, 5 and 50 mg/kg were in the range of 62.6%~115.3% with the relative standard deviations (RSDs) of 2.6%~26.3%. The method can meet the requirements for the determination of the dyes in food samples for import and export inspection.

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Rapid determination of 6 pesticide residues in tomato paste by ultra performance liquid chromatography-tandem mass spectrometry SU Min1, LI Shiyu1, LI Fengge1, GONG Zhiguo1*, WANG Jinhua2 2011, 29 (11):  1070-1075.  DOI: 10.3724/SP.J.1123.2011.01070 Abstract ( 1852 )   [Full Text(HTML)] () PDF (225KB) ( 552 )   An ultra performance liquid chromatography-tandem mass spectrometric method (UPLC-MS/MS) was established for the simultaneous determination of imidacloprid, carbendazim, thiophanate-methyl, propamocarb, methomyl and dimethomorph residues in tomato paste. The samples were extracted by methanol-water (1:1, v/v) containing 0.1%(v/v) acetic acid. The separation was performed on a Waters Acquity UPLC system with a BEH C18 column with the gradient elution of methanol and water (containing 10 mmol/L ammonium acetate). The six pesticides were determined in the modes of electrospray positive ionization (ESI+) and multiple reaction monitoring (MRM). The analytes were quantified by matrix-matched standard solution, and the calibration curves showed good linearity within the concentrations of 0.005 to 0.2 mg/L and the correlation coefficients (r) were more than 0.995. The average recoveries of the six pesticides ranged from 66.8% to 102.9% in the three spiked levels of 0.02, 0.05 and 0.2 mg/kg. The relative standard deviations (RSDs) were all less than 15%. The limits of quantification (LOQ, S/N＞10) were 0.02 mg/kg for the all analytes. The results indicate that the method is easier, faster, more sensitive, and suitable for the qualitative and quantitative confirmation of the six pesticide residues from tomato paste

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Determination of aristolochic acids A and B in Chinese herbals and traditional Chinese patent medicines using ultra high performance liquid chromatography-triple quadrupole mass spectrometry LIU Ying, HAN Shen, FENG Qian, WANG Jinhua* 2011, 29 (11):  1076-1081.  DOI: 10.3724/SP.J.1123.2011.01076 Abstract ( 1865 )   [Full Text(HTML)] () PDF (230KB) ( 624 )   A method for the simultaneous determination of aristolochic acids A and B in some Chinese herbals and traditional Chinese patent medicines by ultra high performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC-MS/MS) was developed. Fourteen samples, including Radix Bupleuri, Radix Glycyrrhizae, Radix Platycodonis, Longdanxieganwan, Xiaopangwan, Slimming Tea, etc., were extracted with methanol-water (70:30, v/v) and purified with Oasis MAX solid-phase extraction cartridges, then analyzed on an Eclipse RP HD C18 column (150 mm×2.1 mm, 1.8 μm) using 5 mmol/L ammonium acetate solution (pH 7.5)-acetonitrile (75:25, v/v) as the mobile phase. The mass spectrometric acquisition was carried out by means of electrospray ionization in positive mode (ESI+) with multiple reaction monitoring (MRM) method. The good linearities (r2＞0.995) were achieved within the ranges of 0.5~200 μg/L and 1~200 μg/L for aristolochic acids A and B, respectively. The limits of detection (LODs) were 5 μg/kg for aristolochic A and 7.5 μg/kg for aristolochic B, and the limits of quantification (LOQs) were 12.5 μg/kg and 25 μg/kg, respectively. The recoveries of aristolochic acids A and B at the spiked levels of 100 μg/kg and 500 μg/kg ranged from 60.3% to 96.4% with the relative standard deviations (RSDs) not more than 10.2%. The results demonstrated that the proposed method is efficient, sensitive, reproducible, reliable and suitable for the trace determination of aristolochic acids A and B in Chinese herbals and traditional Chinese patent medicines.

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Determination of 10 sedative-hypnotics in human plasma using pulse splitless injection technique and gas chromatography-mass spectrometry CHANG Qing1, MA Hongying1*, WANG Fangjie1,2, OU Honglian3, ZOU Ming1,2 2011, 29 (11):  1082-1086.  DOI: 10.3724/SP.J.1123.2011.01082 Abstract ( 2046 )   [Full Text(HTML)] () PDF (188KB) ( 657 )   A simple, precise and sensitive gas chromatography-mass spectrometry (GC-MS) method coupled with pulse splitless injection technique was developed for the determination of 10 sedative-hypnotics (barbital, amobarbital, phenobarbital, oxazepam, diazepam, nitrazepam, clonazepam, estazolam, alprazolam, triazolam) in human plasma. The drugs spiked in plasma were extracted with ethyl acetate after alkalization with 0.1 mol/L NaOH solution. The organic solvent was evaporated under nitrogen stream, and the residues were redissolved by ethyl acetate. The separation was performed on an HP-5MS column (30 m×250 μm×0.25 μm). The analytes were determined and identified using selected ion monitoring (SIM) mode and scan mode, respectively. The internal standard method was used for the determination. The target analytes were well separated from each other on their SIM chromatograms and also on the total ion current (TIC) chromatograms. The blank extract from human plasma gave no peaks that interfered with all the analytes on the chromatogram. The calibration curves for 10 sedative-hypnotics showed excellent linearity. The correlation coefficients of all the drugs were higher than 0.9954. The recoveries of the drugs spiked in human plasma ranged from 92.28% to 111.7%, and the relative standard deviations (RSDs) of intra-day and inter-day determinations were from 4.09% to 14.26%. The detection limits ranged from 2 to 20 μg/L. The method is simple, reliable, rapid and sensitive for the determination and the quantification of 10 sedative-hypnotics in human plasma and seems to be useful in the practice of clinical toxicological cases.

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Preparation and evaluation of amylose and cellulose tris(3-trifluoromethylphenylcarbamates)-based chiral stationary phases JIN Zhaolei1, HU Fangfang2, WANG Yibo1, LIU Guihua2, WANG Fang2, PAN Fuyou2, TANG Shouwan2* 2011, 29 (11):  1087-1092.  DOI: 10.3724/SP.J.1123.2011.01087 Abstract ( 2195 )   [Full Text(HTML)] () PDF (249KB) ( 537 )   To broaden the category of polysaccharide-based chiral stationary phases (CSPs), coated CSPs based on tris(3-trifluoromethylphenylcarbamates) of amylose and cellulose were prepared for enantioseparation in high performance liquid chromatography. Their performances were evaluated by eight racemates using hexane-isopropanol as mobile phase. Compared with the most widely used, commercially available polysaccharide-based CSPs, Chiralpak AD and Chiralcel OD, utilizing tris(3,5-dimethylphenylcarbamates) of amylose and cellulose as the chiral selector, respectively, the obtained CSPs exhibited lower enantioseparation abilities. However, cellulose tris(3-trifluoromethylphenylcarbamate)-based CSP exhibited characteristic enantioseparation and some chiral compounds were better resolved on this CSP than on Chiralcel OD. The chiral recognition abilities of the obtained CSPs were increased with the decrease of the portion of isopropanol in the mobile phase and relatively high enantioseparation was obtained with the mobile phase of hexane-isopropanol (95:5, v/v). The obtained amylosic phase demonstrated slightly higher chiral resolving ability than the cellulosic one for the test racemates. In addition, it was revealed that the enantioseparations of the cellulosic and amylosic CSPs were complementary.

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Retention mechanism of benzoic acid on p-tert-butyl- calix［4］arene-1,2-crown-4 stationary phase HU Kai1, CHEN Kangkang1, ZHANG Huiming1, LIU Junwei1, ZHAO Wenjie1,2, ZHANG Shusheng1* 2011, 29 (11):  1093-1097.  DOI: 10.3724/SP.J.1123.2011.01093 Abstract ( 1760 )   [Full Text(HTML)] () PDF (238KB) ( 513 )   The chromatographic behaviors of benzoic acid (BAH) were investigated on a self-made p-tert-butyl-calix［4］arene-1,2-crown-4 (Cx4-4) stationary phase by changing methanol content and pH value of the mobile phase. The results show that hydrophobic interaction is the main interaction in the separation of benzoic acid, moreover, inclusion interaction, π-π and hydrogen bonding interactions also play additional roles. A Density Functional Theory (DFT) method with the base set of B3LYP/STO-3G* was employed to explain the interaction between BAH and Cx4-4, and the optimized supramolecular structure (Cx4-4 and BAH), the Gibbs free energy change (ΔG) and stabilization energy change (ΔE) were obtained. With the assistance of quantum chemistry calculation, the separation mechanism is further discussed. The quantum chemical calculation results were consistent with the retention behavior of BAH on Cx4-4 stationary phase. Finally, by using the self-made Cx4-4 column, a high performance liquid chromatographic (HPLC) method for the analysis of BAH in tuber mustard and vinegar was developed.

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Determination of niclosamide ethanolamine residue in rice and paddy field by high performance liquid chromatography WU Yihong1,2, GONG Daoxin1,2*, PENG Xiao1,2, XIE Hui1,2, HAN Baolu1,3 2011, 29 (11):  1098-1102.  DOI: 10.3724/SP.J.1123.2011.01098 Abstract ( 2276 )   [Full Text(HTML)] () PDF (168KB) ( 601 )   A high performance liquid chromatographic (HPLC) method was established for the analysis of niclosamide ethanolamine residue in rice and paddy field. The paddy water and plant were extracted with alkaline ethylacetate, while the paddy soil, rice husk and unpolished rice were first extracted with alkaline ethanol, and then with ethylacetate. The extracts were then cleaned-up by a Florisil column and detected by high performance liquid chromatography with an ultraviolet detector (UVD) on a Welchrom C18 column (250 mm×4.6 mm, 5 μm). The calibration curve showed good linearity from 0.01 mg/L to 10.00 mg/L with the correlation coefficient more than 0.9998. The average recoveries of this method were from 93.47% to 100.9% with the relative standard deviations of 1.46%~5.82% at the spiked levels of 0.01~5.00 mg/kg. This method is fast, simple, sensitive, reproducible and practical for the determination of niclosamide ethanolamine residue in paddy fields, and can meet the requirement of the determination of pesticide residues.

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Determination of trigonelline in coffee powder and instant coffee by ultrasonic extraction and high performance liquid chromatography LIU Hongcheng, LI Qiwan*, SHAO Jinliang, YAN Hongmei, LAN Shanshan 2011, 29 (11):  1103-1106.  DOI: 10.3724/SP.J.1123.2011.01103 Abstract ( 2182 )   [Full Text(HTML)] () PDF (143KB) ( 607 )   A method of high performance liquid chromatography was established for the analysis of trigonelline in coffee powder and instant coffee. The separation was performed on a BondPak NH2 column (250 mm×4.6 mm, 5 μm). The mobile phase was methanol-water (82:18, v/v) at a flow rate of 0.8 mL/min. The detection wavelength was set at 260 nm. The method had good linearity in the range of 1~40 mg/L (the correlation coefficient was 0.9998). The repeatability of the method was performed at one day, different days, and by two analysts. The accuracy of the method was evaluated by recovery study. The recoveries were more than 90% with the relative standard deviations less than 3%. The contents of trigonelline in samples were assessed with ultrasonic extraction and hot water extraction, separately, and the regression coefficient between trigonelline contents obtained under the two extraction methods was 0.9964. The method is simple, rapid, highly sensitive, and suitable for the analysis of trigonelline and quality control of coffee samples.

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Determination of 5-hydroxytryptamine in plasma by nanofiber solid phase extraction-high performance liquid chromatography ZHOU Xiaoling1, WANG Yu1, CHEN Liqin1, KANG Xuejun1,2* 2011, 29 (11):  1107-1111.  DOI: 10.3724/SP.J.1123.2011.01107 Abstract ( 1904 )   [Full Text(HTML)] () PDF (228KB) ( 547 )   1. Key Laboratory of Child Development and Learning Science (Ministry of Education), Southeast University, Nanjing 210096, China; 2. Research Institute of Southeast University in Suzhou, Suzhou Key Laboratory of Environment and Biosafety, Suzhou 215123, China) Abstract: A novel packed-nanofiber solid phase extraction coupled with high performance liquid chromatography-electrochemical detection (HPLC-ECD) method was established for the determination of 5-hydroxytryptamine (5-HT) in plasma. A 10% (v/v) HClO4 solution was used to precipitate the protein in plasma samples. After homogenizing for 1 min and centrifuging for 10 min at 12000 r/min, the supernatant was adjusted to pH 8.5 with 0.1 mol/L sodium tetraphenylborate and then derivatized with o-phthalaldehyde (OPA) solution at 30 ℃ for 4 min. The solution was then purified and preconcentrated by the packed-nanofiber solid phase extraction column, in which methanol was used as the eluent. The analyte was analyzed by HPLC-ECD. The chromatographic separation was achieved on a Shimadzu C18 column with pH 5.4 0.05 mol/L phosphate buffer solution (containing 0.25 mmol/L ethylene diamine tetraacetic acid)-methanol (60:40, v/v) as mobile phase. The linear range was 5~500 μg/L with the correlation coefficient (r2) of 0.9996. The limit of detection (S/N=3) was 1 μg/L. And the spiked recoveries were in the range of 95.6%~101.4% with the relative standard deviations (RSDs) of intra-day and inter-day assays below 5% (n=3). On the basis of the advantages of simplicity, high sensitivity and good reproducibility, this method can be used for the determination of 5-HT in human plasma.

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Preparative isolation and purification of five non-volatile compounds from Fructus Caryophylli and Flos Caryophylli by high-speed counter-current chromatography GAO Lu, YU Bo*, YANG Hong 2011, 29 (11):  1112-1117.  DOI: 10.3724/SP.J.1123.2011.01112 Abstract ( 2234 )   [Full Text(HTML)] () PDF (257KB) ( 488 )   A high-speed counter-current chromatographic (HSCCC) method was successfully developed for the isolation of three non-volatile compounds from Fructus Caryophylli and two chromone compounds from Flos Caryophylli. The optimum separation solution systems included system A (n-hexane-ethyl acetate-methanol-water (5:8:6:13, v/v/v/v) and system B (n-hexane-ethyl acetate-methanol-water (5:8:9:10, v/v/v/v). The upper phase of the system A was used as the stationary phase, and the lower phases of the systems A and B as the mobile phases were operated at a flow of 1.2 mL/min, while the apparatus rotated at 880 r/min. The 12.3 mg of ellagic acid, 9.6 mg of rhamnetin, 17.2 mg of quercetin were successfully purified from 70 mg of the crude extract of Fructus Caryophylli by a two-step separation. In the same way, 10.2 mg of 5,7-dimethoxy-2-methylchromone, 8.6 mg of 5,7-dimethoxy-2,6-dimethylchromone were purified from 50 mg of the crude extract of Flos Caryophylli. The purities of the compounds were all over 96% as determined by high performance liquid chromatography (HPLC). The five compounds were indentified by mass spectrometry (MS), 1H-nuclear magnetic resonance (NMR) and 13C-NMR. The results indicate that HSCCC is a powerful technique for the purification of non-volatile compounds from different parts of Eugenia caryophylla Thunb.

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Determination of solubility parameters of high density polyethylene by inverse gas chromatography WANG Qiang, CHEN Yali, LIU Ruiting, SHI Yuge, ZHANG Zhengfang, TANG Jun* 2011, 29 (11):  1118-1121.  DOI: 10.3724/SP.J.1123.2011.01118 Abstract ( 2571 )   [Full Text(HTML)] () PDF (181KB) ( 687 )   Inverse gas chromatographic (IGC) technology was used to determine the solubility parameters of high density polyethylene (HDPE) at the absolute temperatures from 303.15 to 343.15 K. Six solvents were applied as test probes including hexane (n-C6), heptane (n-C7), octane (n-C8), nonane (n-C9), chloroform (CHCl3) and ethyl acetate (EtAc). Some thermodynamic parameters were obtained by IGC data analysis such as the specific retention volumes of the solvents (V0g), the molar enthalpy of sorption (ΔHS1), the partial molar enthalpy of mixing at infinite dilution (ΔH∞l), the molar enthalpy of vaporization (ΔHv), the activity coefficients at infinite dilution (Ω∞1), and Flow-Huggins interaction parameters (χ∞1,2) between HDPE and probe solvents. The results showed that the above six probes are poor solvents for HDPE. The solubility parameter of HDPE at room temperature (298.15 K) was also derived as 19.00 (J/cm3)0.5.

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Determination of seven aromatic amines in hair dyes by capillary electrophoresis coupled with field-amplified sample stacking LU Yuchao1, WANG Haiyan1, SONG Pingping1, LIU Shuhui1,2* 2011, 29 (11):  1122-1127.  DOI: 10.3724/SP.J.1123.2011.01122 Abstract ( 2164 )   [Full Text(HTML)] () PDF (257KB) ( 506 )   A method for the determination of 4,4′-methylenedianiline, aniline, o-anisidine, 3,4-dimethylaniline, p-anisidine, 3-aminophenol, 1-naphthylamine in hair dyes was established by capillary electrophoresis coupled with field-amplified sample stacking. The optimum running buffer was an aqueous solution containing 0.15 mol/L NaH2PO4 and 0.015 mol/L trolamine (pH 2.3), and the baseline separation was achieved within 6.5 min. The effects of phosphoric acid and acetonitrile concentration in the sample matrix, the length of the preinjection water plug, and the sample injection voltage and time on the stacking efficiency were investigated. The optimum stacking conditions for the real samples included a water plug of 3.45 kPa (0.5 psi)×6 s, the addition of 40%(v/v) acetonitrile and 0.6×10~3mol/L phosphoric acid to the sample solution and a sample injection of 10 kV×10 s. The seven analytes all showed good linearities (R2＞0.996) within 3~1000 μg/L, with the detection limits in the range of 0.26~2.75 μg/L. The method was shown to provide over 1~3 magnitudes of sensitivity enhancement. 3-Aminophenol was found in two black hair dyes, and the amounts were 7.32 mg/g and 1.34 mg/g, individually. The recoveries ranged from 74%~108%. The proposed approach may find widespread applications for the determination of trace aromatic amines and other cationic analytes in various sample matrixes.

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Determination of penicillin intermediate and three penicillins in milk by high performance capillary electrophoresis TIAN Chunqiu1, TAN Huarong2*, GAO Liping3, SHEN Huqin1, QI Kezong1 2011, 29 (11):  1128-1132.  DOI: 10.3724/SP.J.1123.2011.01128 Abstract ( 1850 )   [Full Text(HTML)] () PDF (211KB) ( 566 )   A high performance capillary electrophoresis (HPCE) method was developed for the simultaneous determination of penicillin intermediate and penicillins in milk, including 6-amino-penicillanic acid (6-APA), penicillin G (PEN), ampicillin (AMP) and amoxicillin (AMO). The main parameters including the ion concentration and pH value of running buffer, separation voltage and column temperature were optimized systematically by orthogonal test. The four penicillins (PENs) were baseline separated within 4.5 min with the running buffer of 40 mmol/L potassium dihydrogen phosphate-20 mmol/L borax solution (pH 7.8), separation voltage of 28 kV and column temperature of 30 ℃. The calibration curves showed good linearity in the range of 1.56~100 mg/L, and the correlation coefficients (r2) were between 0.9979 and 0.9998. The average recoveries at three spiked levels were in the range of 84.91%~96.72% with acceptable relative standard deviations (RSDs) of 1.11%~9.11%. The method is simple, fast, accurate and suitable for the determination of penicillins in real samples.

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Determination of forchlorfenuron and gibberellin acid in the grapes using high performance liquid chromatography-tandem mass spectrometry ZHANG Jun1*, DU Ping2 2011, 29 (11):  1133-1136.  DOI: 10.3724/SP.J.1123.2011.01133 Abstract ( 1900 )   [Full Text(HTML)] () PDF (171KB) ( 643 )   A method was established for the determination of two plant growth regulators, forchlorfenuron (CPPU)and gibberellin acid (GA3), in the grapes using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample was extracted with 0.5%(v/v) formic acid aqueous solution and acetonitrile (4:1, v/v), and cleaned-up with Strata-X solid phase extraction cartridge. The separations were performed on an Agilent SB-C18 column (50 mm×2.1 mm, 1.8 μm), with a mobile phase of 0.5% formic acid aqueous solution-acetonitrile at a flow rate of 0.3 mL/min and detected by electrospray ionization MS/MS under the multiple reaction monitoring (MRM) mode. The results showed that the good linear relationships and the correlation coefficients greater than 0.999 were obtained. The limits of detection (LODs) were 0.5 μg/L and 0.3 μg/L for CPPU and GA3, respectively. The limits of quantification (LOQs) were 2.0 μg/L and 1.0 μg/L for CPPU and GA3, respectively. The recoveries were 91.7%~95.6% and 90.3%~94.2% with the relative standard deviations (RSD) of 4.1%~7.3% and 3.2%~6.9% for CPPU and GA3, respectively. The results indicate that the method is accurate and can be used for the determination of CPPU and GA3 residues in the grapes.

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Enantiomeric separation of trantinterol hydrochloride by high performance liquid chromatography on cellulose derivative-based chiral stationary phase JIANG Minyan1, QIN Feng1, XIONG Zhili1, ZHANG Shangshang1, PAN Li2, LI Famei1* 2011, 29 (11):  1137-1140.  DOI: 10.3724/SP.J.1123.2011.01137 Abstract ( 1990 )   [Full Text(HTML)] () PDF (148KB) ( 481 )   A high performance liquid chromatographic (HPLC) method using cellulose tris-(3,5-dimethylphenylcarbamate) as chiral stationary phase (Lux Cellulose-1) for the separation of trantinterol hydrochloride enantiomers was developed. The method was based on normal phase model with n-heptane as the basal solvent of mobile phase. The influences of organic modifiers, mobile phase additives and column temperature on the retention and separation of the enantiomers were examined and discussed. It was demonstrated that the mobile phase additives had a dominant effect on the enantiomeric separation. No separation was observed with the addition of diethylamine only in the mobile phase, while the retention was increased and the enatiomeric separation was observed with the addition of trifluoroacetic acid. When both trifluoroacetic acid and diethylamine were added into the mobile phase, the enantioseparation was significantly improved with a resolution up to 4.0. Ethanol and isopropanol were investigated as the organic modifiers, and ethanol offered a better enatiomeric resolution for trantinterol hydrochloride. In the examined temperature range between 15 ℃ and 35 ℃ both separation factor and resolution were decreased with the increase of the column temperature. The optimized chiral HPLC method for the separation of trantinterol hydrochloride enantiomers involved a Lux Cellulose-1 column (250 mm×4.6 mm, 5 μm), a mobile phase of n-heptane/ethanol/trifluoroacetic acid/diethylamine (88:12:0.3:0.05, v/v/v/v) at a flow rate of 1.0 mL/min, a detection at 246 nm and a column temperature of 25 ℃. The method is simple and rapid for the enantiomeric impurity determination of (~)-trantinterol hydrochloride bulk samples.

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Determination of trace carbaryl and carbofuran in water by online column enrichment-ultra high performance liquid chromatography WANG Enzhi1, YANG Xinlei2, YE Mingli2, WANG Qiong2, CAI Xiaojun3* 2011, 29 (11):  1141-1144.  DOI: 10.3724/SP.J.1123.2011.01141 Abstract ( 1827 )   [Full Text(HTML)] () PDF (217KB) ( 507 )   An online column enrichment-ultra high performance liquid chromatography (UHPLC) method was developed to determine trace carbaryl and carbofuran in water. The sample was injected into a UHPLC system directly after filtration with 0.22 μm membrane, and then enriched by online solid phase extraction (SPE) column. The analyte was back-flushed into the analytical column Acclaim RSLC C18 (100 mm×2.1 mm, 2.2 μm) by valve switching method. The mobile phases were 10 mmol/L ammonium acetate buffer (pH 5.0, adjusted by acetic acid) and acetonitrile in a gradient elution mode with a flow rate of 0.8 mL/min, and detected by a diode array detector with the detection wavelength of 280 nm. The good linear ranges of carbaryl and carbofuran were 1.0~100 μg/L with the correlation coefficients (r2) larger than 0.9999, and the limits of detection (S/N=3) were 0.5 μg/L and 0.25 μg/L, respectively. The average spiked recoveries were in the range of 76.0%~120.0%. The method has been applied to determine trace carbaryl and carbofuran in water samples with satisfactory results.