1,2-萘醌-4-磺酸钠分光光度法测定苯丙氨酸

Spectrophotometric determination of Phenylalanine using sodium 1,2-naphthoquinone-4-sulfonate as a chromogenic reagent

建立了用1,2-萘醌-4-磺酸钠测定苯丙氨酸的方法。在pH 10．0的缓冲溶液中,苯丙氨酸与1,2-萘醌-4-磺酸钠反应形成组成比为1：1的浅红色产物,其最大吸收波长λmax=474nm,表观摩尔吸光系数ε=9. 5×10^3 L /（ mol·cm）。苯丙氨酸浓度在0．15~20 mg·L^-1范围内呈良好的线性关系,线性回归方程为 A=0．011＋0．0576c（mg·L^-1）,线性相关系数r=0．9995,平均回收率在99．0%以上,本法用于测定药物样品中苯丙氨酸的含量,结果满意。

A rapid ,simple and sensitive method for the determination of phenylalanine using sodium 1,2-naphthoquine-d-sulfonate as a chromogenic reagent is established in this paper. It is based on the fact that a pink product can be formed by the reaction be- tween phenylalanine and sodium 1,2-naphthoquine-4-sulfonate in pill0.0 buffer solution,and the stoichiometric ratio of the product is 1：1. Beer＇s law is obeyed in a range of 0. 15 -20 mg·L^-1 for phenylalanine at the maximum absorption of474nm（ε=9. 5×10^3 L · mol^-1 cm^-1 ）. The linear regression equation of the calibration curve is A = 0. 011 ＋0. 0576c （ mg·L^-1 ）, with a correlation coefficient of 0. 9995. The average recovery is over 99.0%. This proposed method has been successfully applied to the determination of phenyl- alanine with satisfactory results.