A Method of Determining the Amount of Tryptophan in Wool by Hydrolysis with Sulphuric Acid for Short Periods

Abstract

A method is described for determining the tryptophan content of proteins, particularly wool. The wool is hydrolysed in sulphuric acid for 2 h at 70°C and the tryptophan is determined colorimetrically. The method is quicker and more reproducible than previously used methods. The tryptophan contents of wool that had been modified by heating, treatment with chlorine, bleaching with hydrogen peroxide or exposure in a Fade‐Ometer, determined using this method, are compared with those determined by other methods.