毛细管电泳法测定淫羊藿甙的pK_a值及其在中药淫羊藿中的含量

 利用毛细管电泳中不同 pH条件下有效淌度 (μeff)与缓冲溶液中氢离子的浓度 (H+])的非线性关系以及1/ μeff与缓冲溶液中 H+]的线性关系 ,测定了淫羊藿甙的离子淌度 (μA- )和pKa 值 ;考察了在有机改性剂存在的情况下 ,随缓冲溶液中有机改性剂浓度的增加 ,淫羊藿甙的 pKa 值的变化情况。在缓冲溶液为V(2 4mmol/L磷酸盐 )∶V(乙醇 ) =70∶30时 ,对中药淫羊藿中淫羊藿甙的含量进行了定量测定 ,结果发现校正峰面积 (Y)与淫羊藿甙的质量浓度 (X ,g/L)的线性相关方程为Y =6 96× 10 -3 + 17 0X ,线性范围为 0 0 32g/L～ 0 35 4g/L。

Determination of the pKa Value of Icariin and Its Content in the Chinese Herb Medicine Epimedium Grandiflorum Morr.by Capillary Electrophoresis

Knowledge of dissociation constants is important for prediction and understanding the migration behavior of analytes in capillary electrophoresis. Icariin is the active component of the Chinese herb medicine Epimedium grandiflorum Morr.. In order to determine the dissociation constant of icariin and to show many important pharmacology activities, a CZE method has been used to determine the ion mobility (mu A-) and the pKa value of icariin based on the non-linear relation between mu eff and H+] and the linear relation between the reciprocal of effective mobility of the solute (1/mu eff) and the H+] of the buffer solution. In addition, the change of pKa of icariin with the increase of ethanol concentration in the buffer was also investigated. Under the buffer condition of 24 mmol/L phosphate + 30% ethanol, the content of the active component icariin in Chinese herb Epimedium grandiflorum Morr. was quantitatively determined. The linear correlation equation was Y = 6.96 x 10(-3) + 17.0X, and the linear range is 0.032 g/L-0.354 g/L.