Separation of the higher monoamino-acids by counter-current liquid-liquid extraction: the amino-acid composition of wool.

THE possibility of employing counter-current liquid'liquid-extraction for the separation of amino-acids in the form of acyl derivatives from protein 'hydrolysates was briefly discussed by Synge [1939, 1-4], who described preliminary experiments on the separation of some of the naturally occurring 'monoaminoacids'. In the present paper we review the literature on counter-current liquidliquid extraction, discuss the mathematical and physical basis of the separation of acylamino-acide by liquid-liquid extraction, and describe the construction, operation and testing of a multi-plate chloroform-water counter-current extraction train. We then describe the use of this machine in a control analysis of a known mixture of amino-acids for such components as methionine, valine, proline, the leucines and phenylalanine, together with the application of the new technique to an analysis of wool for these amino-acids. In conclusion we compare the results with those obtained by other methods, and summarize existing knowledge of the amino-acid composition of wool.