A Rapid Method for determining the Concentration of Ammonium Sulphate Solutions

Abstract

THE separation of proteins and enzymes by the ammonium sulphate gradient elution technique has been reported by a number of workers^1–4. Dixon⁵ and Kunitz⁶ have published a useful nomogram and equation, respectively, for use in the preparation of ammonium sulphate solutions. While the concentration of ammonium sulphate in a solution can be determined by the usual methods (that is, by distillation and titration, by specific-gravity determinations, nesslerization, or by gravimetric methods) they are all time-consuming, often involve large dilutions of the sample and, in general, are not useful for the routine analysis of a large number of samples. The use of refractometry has been investigated in the search for a more rapid method of measuring the concentration of ammonium sulphate in the fractions collected by the gradient elution technique as well as in the classical precipitation method.