Analytical separations by high-voltage paper electrophoresis. Amino acids in protein hydrolysates

Abstract

An apparatus and experimental details for high-voltage paper electrophoresis under conditions of constant temperature and paper wetness are described. The application of the method to the separation of the amino acids commonly occurring in protein hydrolysates is described. Eighteen amino acids can be separated completely, by three electrophoretic experiments at pH 5.2, 1.85 and 1.81, at potential gradients of 70-100v/cm. The mobilities of several amino acid cations relative to alanine are tabulated, and a method for calculation of these mobilities from the net charge and diffusion constant is described and compared with experiment. A method of quantitative determination of the resolved amino acid zones by use of the cadmium-ninhydrin reaction is described, and analyses of synthetic amino acid mixtures and replicate analyses of hydrolysates of performic acid-oxidized insulin are given to illustrate the utility of the method.