New Cysteine Fluorometric Determination for Vegetables and Fruits Based on a Reaction with 2, 6-Dichloro-p-benzoquinone and Using Thin-layer Densitometry

Abstract

A microfluorometric method for the determination of cysteine was developed using 2, 6-dichloro-p-benzoquinone. 2, 6-Dichloro-p-benzo-quinone reacts quantitatively with cysteine in an acidic solution, and the reaction product is fluorescent. The assay was applied to vegetables and fruits by using TLC densitometry. The method is simple and rapid, and cysteine samples can be determined both qualitatively and quantitatively with comparatively high sensitivity (as little as 80pmol) by the reported procedure.