比色法测定复方氨基酸注射液中胱氨酸含量

目的建立测定复方氨基酸注射液(18AA)中胱氨酸的含量方法。方法在碱性条件下,用1,4-二硫代苏糖醇将胱氨酸还原成半胱氨酸,生成的半胱氨酸与酸性茚三酮溶液反应,生成红色产物,在558nm波长处测定吸光度,用对照品标准曲线法测定注射液中胱氨酸的含量。结果胱氨酸在0～0.08mg/ml范围内呈良好的线性关系(r=0.9998),平均回收率为99.0%,RSD(n=9)为0.51%。结论本法准确、质量可控,可测定复方氨基酸注射液中胱氨酸的含量。

Colorimetric determination of cystine in compound amino acids injection

Purpose To establish a method for the determination of cystine in compound amino acids injection(18AA). Methods Dithiothreitol solution was used to reduce cystine to cysteine under alkaline conditions.A red product which was formed after the acid ninhydrin reagent added into the cysteine could be determined at 558 nm by spectrophotometric method. Under the same condition, the amount of cystine in the sample was calculated by reference to a obtained calibiration curve. Results Cystine showed a good linearity...