The quantitative isolation of valine from amino acid mixtures as its dinitrophenyl derivative

Abstract

A method is described for the quantitative determination of valine as its dinitrophenyl derivative. It is simple, accurate and requires no special apparatus. The range is 0.1-1.5 [mu]moles of valine and several determinations may be done in parallel. Recoveries of valine were good even when less than 1 [mu]g. of valine was used so that the amounts present had to be determined in terms of radioactivity. The valine content of a purified insulin sample, determined by this method, agreed closely with the calculated value.