title: On-line two-step stacking in capillary zone electrophoresis for the preconcentration of strychnine and brucine.
abstract: An on-line sample preconcentration method by two-step stacking i.e., sweeping and micelle to solvent stacking, in capillary zone electrophoresis (CZE) has been developed for the determination of strychnine and brucine in traditional Chinese herbal medicines. After experimental optimizations, the best separation was achieved by using 75 mM phosphate buffer (pH 2.5) with 30% methanol (v/v). Compared with normal CZE injection, 51- and 38-fold improvement in concentration sensitivity was achieved for strychnine and brucine, respectively. The calibration curve was linear in the range of 0.1-5.0 μg mL(-1) for both strychnine and brucine, with the correlation coefficients of 0.9998 and 0.9997, respectively. The limits of detection (S/N=3) for both alkaloids were 0.01 μg mL(-1). The inter-day (n=8) and intra-day (n=5) reproducibilities expressed as the relative standard deviations for corrected peak area were less than 9.5%. The method was applied to determine strychnine and brucine in two Chinese herbal medicines, with recoveries ranging from 94.2% to 105.4%. The results indicated that the method is simple, rapid, reliable, and can be applied to determine strychnos alkaloids in traditional Chinese herbal medicines.
authors: Department of chemistry, College of Science, Agricultural University of Hebei, Baoding 071001, PR China.
authors: Xiumin
authors: X
authors: Yang
authors: Department of chemistry, College of Science, Agricultural University of Hebei, Baoding 071001, PR China.
authors: Shuaihua
authors: S
authors: Zhang
authors: Department of chemistry, College of Science, Agricultural University of Hebei, Baoding 071001, PR China.
authors: Juntao
authors: J
authors: Wang
authors: Department of chemistry, College of Science, Agricultural University of Hebei, Baoding 071001, PR China.
authors: Chun
authors: C
authors: Wang
authors: Department of chemistry, College of Science, Agricultural University of Hebei, Baoding 071001, PR China. Electronic address: wangzhi@hebau.edu.cn.
authors: Zhi
authors: Z
authors: Wang
mesh_terms: D002138:Calibration; D004365:Drugs, Chinese Herbal / Q000302:isolation & purification; D019075:Electrophoresis, Capillary / Q000295:instrumentation*; D004867:Equipment Design; D057230:Limit of Detection; D008823:Micelles; D013331:Strychnine / Q000031:analogs & derivatives* / Q000302:isolation & purification*
chemical_list: D004365:Drugs, Chinese Herbal; D008823:Micelles; C083806:brucine; D013331:Strychnine
keywords: Alkaloid; Capillary zone electrophoresis; Micelle-to-solvent stacking; On-line sample preconcentration; Sweeping