Stepwise injection spectrophotometric determination of cysteine in biologically active supplements and fodders

• Published in: Microchemical journal Vol. 110; pp. 369 - 373
• Main Authors: Bulatov, Andrey V., Petrova, Anastasiia V., Vishnikin, Andriy B., Moskvin, Leonid N.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-09-2013
• Subjects: Cysteine; Flow-batch analysis; Spectrophotometry; Stepwise injection analysis; Flow-batch analysis; Cysteine; Spectrophotometry; Stepwise injection analysis
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/j.microc.2013.04.020

A stepwise injection analysis system was developed to monitor the concentration of l-cysteine in biologically active supplements (BAS) and fodders. It is based on the rapid redox reaction of l-cysteine with 18-molybdo-2-phospahte heteropoly anion (18-MPA) and the detection of the formed heteropoly blue with a spectrophotometry. The method has relatively wide optimal ranges of pH and 18-MPA concentration −5.0 to 7.3 and 0.4 to 2.0mM, respectively. Under optimized operating conditions the performance of the SWIA system was linear up to a concentration of l-cysteine of 0.1mM (R2=0.994) with a detection limit of 0.003mM and a sample frequency of 20h−1. The SWIA system was employed to determine the concentration of l-cysteine in BAS and fodder. The obtained data were in good agreement with those measured by a HPLC method.
•A simple and automated method for the spectrophotometric determination of cysteine•Rapid and selective reaction between ammonium 18-molybdo-2-phosphate and cysteine•Method allows the determination of cysteine with a detection limit of 0.003mM and a sample frequency of 20h−1.•SWIA method was applied to the determination of cysteine in biologically active supplements and fodders.