Modified ninhydrin spray reagent for the identification of amino acids on thin-layer chromatography plates

Abstract

Identification of amino acids is essential for the evaluation of protein structure and also for the determination of the presence of amino acids in natural products. D-Camphor-10-sulphonic acid–ninhydrin can produce various distinguishable colours when it reacts with amino acids, whereas ninhydrin itself produces the same purple colour with most of them. The detection limits for amino acids for the proposed spray reagent range between 0.4 and 2.0 µg, under cold conditions, and 0.2 and 1.0 µg, after heating.