托吡卡胺对映体的毛细管电泳-方波安培分离检测

Enantioseparation of Tropicamide by Capillary Electrophoresis with Square Wave Amperometric Detection

采用毛细管电泳 方波安培检测法,在熔融石英毛细管(75μmi.d.×50cm)中,以7mmol/L三羟甲基氨基甲烷(Tris) 10mmol/L柠檬酸 2mmol/L硼酸 15mmol/Lβ 环糊精(β CD)(pH3 0)为电泳介质,采用重力进样,高度差为20cm,进样时间为10s,在分离电压为15kV,方波平衡电位+0 8V的条件下,实现了托吡卡胺对映体的分离检测。线性范围为5～750μmol/L,检出限为2μmol/L。对影响分离度的因素β CD浓度、硼酸浓度及pH值进行了详细的讨论。将该法应用于复方托吡卡胺滴眼液中托吡卡胺对映体的分离检测,取得了满意结果。

An enantioseparation method for tropicamide by high performance capillary electrophoresis with square wave amperometric detection (SWAD) was developed. The enantiomers of tropicamide were baseline separated in 16 min with an uncoated fused-silica capillary (75 (μm i.d.)×50 cm) under the optimum conditions: 7 (mmol/L) Tris-10 (mmol/L)citric acid-2 (mmol/L) H_3BO_3-15 (mmol/L) β-cyclodextrin (β-CD) (pH 3.0) as background electrolyte, SWAD balance potential (E_b) +0.80 V (vs.Ag/AgCl), separation voltage 15 kV, injection height 20 cm, and injection time 10 s. The calibration curve of the enantiomers showed good linearity in the range from 5 (μmol/L) to 750 (μmol/L) with detection limit of 2 (μmol/L). The average recoveries of added standards were 96%-103%. The effects of the concentrations of β-CD and the boric acid, the pH of the background electrolyte on resolutions (R_s) of the enantiomers were discussed in details. The proposed method was applied to the determination of a commercial tropicamide eye-drops sample without pre-treatment, and satisfactory results were obtained.