Simple, rapid quantitative determination of amino-acids by thin-layer chromatography

Abstract

A simple, rapid method for the quantitative determination of complex mixtures of amino-acids is described. After separation on thin layers of cellulose mounted on flexible plastic sheets, the chromatograms are sprayed with ninhydrin and developed under controlled conditions. The spots are cut out and eluted with 2 ml of 50 per cent. Propyl alcohol and the optical density at 570 nm determined with a microspectrophotometer. From 4 to 6 chromatograms can be eluted and read in 1 day. An accuracy of about 5 nmoles is obtained over a range of 12·5 to 50 nmoles. At higher concentrations, accuracy is within ±10 per cent. Standard graphs are reproducible for at least 5 months.