毛细管电泳电化学检测法同时测定三种氨基酸的电离常数

Determination of ionization constants of amino acids by capillary electrophoresis with electrochemical detection

利用自制微圆盘铜电极,建立了一种毛细管电泳电化学检测同时测定色氨酸、丝氨酸和半胱氨酸pKa值的新方法。在不同pH条件下测定各氨基酸的有效淌度(μeff),利用Origin软件对μeff-[H+]按理论关系式进行非线性拟合,得到其pKa值。该方法简便、快速,测定值与文献值符合良好。

A new method based on a nonlinear model for the determination of ionization constants （pKα） of three amino acids （tryptophan, serine and cystein） by capillary zone electrophoresis with electrochemical detection has been de-veloped. Effective mobilities （μeff） of the amino acids were determined at diferent pH values. According to the theo-retical equation, a nonlinear fitting was made between μeff and the concentrations of hydrogen ion （[ H^＋ ] to get theionization constants of amino acids. The pKα values obtained for amino acids were in well agreement with those in theliteratures.