Spectrophotometric determination of cysteine by complexation with iron(III) using reversed flow injection analysis (R-FIA)

摘要

A simple spectrophotometric flow injection analysis (FIA) method has been developed for the assay of cysteine.In this method a purple colored complex of cysteine and iron (III) was monitored at a wavelength of 545 nm.The optimum operating conditions for the quantitative assays fo cysteine were,pH 9.7,flow rate,2.6 ml/min; coil length, 50 cm; and sample loop size,85#mu#L.Beer's law was obeyed for the range 500-2500 ppm with a correlation coefficient of 0.9996.The maximum relative standard deviation was 1.73% (n=10).Other amino acids tested show minimum or no interference when analyzed in mixtures with cysteine.