毛细管电泳-激光诱导荧光用于中药制剂中氨基酸成分的分析

建立了一种用于测定中药制剂中氨基酸成分的毛细管电泳-荧光检测方法. 用含有α-环糊精(α-CD)的硼砂缓冲溶液为背景电解质, 经异硫氰酸荧光素(FITC)衍生的5种氨基酸在50 min内可以得到很好的分离和测定. 考查了各个分离参数对分离的影响, 得到的优化条件为: 含45 mmol/L的α-环糊精的80 mmol/L硼砂缓冲溶液(pH值9.2)作为背景电解质, 分离电压20 kV; 柱温22 ℃. 衍生试剂FITC与单个氨基酸的化学计量比为4∶1时, 能够获得稳定荧光强度的氨基酸衍生物. 在优化条件下, 各氨基酸成分在73.5～2900 nmol/L 的浓度范围内呈良好的线性关系(相关系数r2为0.9906～0.9998). 保留时间和峰面积的相对标准偏差分别为0.8%～3.0%和0.7%～5.7%, 检测限(3倍信噪比)为3.5～35 nmol/L. 该方法准确可靠, 可用于质量控制为目的的中药制剂中氨基酸成分的定量测定.

Determination of Amino Acid in Formula of Traditional Chinese Medicine Using Capillary Electrophoresis Coupled with Laser-Induced Fluorescence Detection

A method for determination of amino acids in the formula of traditional Chinese medicine (TCM) by capillary electrophoresis (CE) with detection of laser-induced fluorescence (LIF) have been developed. Fifteen amino acids in the formula of the Chinese traditional medicine which derivatized with fluorescein isothiocyanate were finely separated and determinated by CE with borate buffer containing α-cyclodextrin as buffer additive. The separation parameters were investigated to give an optimal experimental conditions: borate buffer (80 mmol/L, pH 9.2) containing 45 mmol/L α-cyclodextrin; applied voltage, 20 kV; column temperature, 22 ℃. All amino acids were separated within 50 min. All amino acid-FITC derivatives is linear in the concentration range from 73.5 to 2900 nmol/L (r2＝0.9906～0.9998). The relative standard deviations (n＝6) of the method were 0.8%～3.0% for migration time and 0.7%～5.7% for peak area except cysteine (5.7%). The detection limits for amino acids were determined in the range from 3.5 to 35 nmol/L at a signal-to-noise ratio of three. This method allows to determining the amino acids in formula of TCM with high sensitivity.