Pérez-Ruiz T, Martínez-Lozano C, Tomás V, Lambertos G
Department of Analytical Chemistry, University of Murcia, Murcia, Spain.
Talanta. 1991 Nov;38(11):1235-9. doi: 10.1016/0039-9140(91)80098-k.
A flow-injection configuration is proposed for the individual determination of cysteine and cystine and for the mixtures of both analytes. The procedure is based on the inhibitory effect of cysteine on the oxidation of thiamine to thiochrome by mercury(II). Linear calibration graphs were obtained between 1.0 x 10(-5) and 1.0 x 10(-4)M, with a sampling rate of 22 samples/hr and relative standard deviation of 1.14%. The inclusion of a selecting valve in the configuration, to pump water or hydroxylamine, allows the successive determination of these two analytes. The applicability of the method to the determination of cysteine and cystine in pharmaceutical preparations was demonstrated by investigating the effect of potential interferences and by the analysis of commercial preparations.
提出了一种流动注射配置，用于单独测定半胱氨酸和胱氨酸以及这两种分析物的混合物。该方法基于半胱氨酸对汞（II）将硫胺氧化为硫色素的抑制作用。在1.0×10（-5）至1.0×10（-4）M之间获得了线性校准曲线，采样率为每小时22个样品，相对标准偏差为1.14%。在该配置中包含一个选择阀，用于泵送水或羟胺，从而可以连续测定这两种分析物。通过研究潜在干扰的影响以及对市售制剂的分析，证明了该方法在药物制剂中测定半胱氨酸和胱氨酸的适用性。
