Department of chemistry, College of Science, Agricultural University of Hebei, Baoding 071001, PR China.
Department of chemistry, College of Science, Agricultural University of Hebei, Baoding 071001, PR China.
Anal Chim Acta. 2014 Mar 3;814:63-8. doi: 10.1016/j.aca.2014.01.027. Epub 2014 Jan 21.
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.
建立了一种两步富集在线样品预处理方法，即胶束电动色谱（MEKC）中的扫集和胶束增敏溶剂萃取，用于测定中草药中的士的宁和马钱子碱。通过实验优化，在 75 mM 磷酸盐缓冲液（pH 2.5）中，甲醇体积分数为 30%时，获得了最佳分离条件。与普通 MEKC 进样相比，士的宁和马钱子碱的浓度灵敏度分别提高了 51 倍和 38 倍。士的宁和马钱子碱的校准曲线在 0.1-5.0 μg mL(-1)范围内呈线性，相关系数分别为 0.9998 和 0.9997。两种生物碱的检测限（S/N=3）均为 0.01 μg mL(-1)。日内（n=8）和日间（n=5）精密度（以校正峰面积的相对标准偏差表示）小于 9.5%。该方法用于两种中草药中士的宁和马钱子碱的测定，回收率在 94.2%-105.4%之间。结果表明，该方法简单、快速、可靠，可用于测定中草药中的士的宁生物碱。
