A method for the determination of D-galactosamine in the presence of D-glucosamine.

The specificity of the reaction for amino sugars discovered by Elson & Morgan (1933) has been increased by several workers through knowledge of some of the intermediates involved. The interference by amino acids and glucose was overcome in different ways (Schloss, 1951; Immers & Vasseur, 1952; Cessi, 1952; Cessi & Piliego, 1960). The separation of a volatile fraction among the products of condensation of amino sugars with pentane-2,4-dione (acetylacetone) (Schloss, 1951), later identified as 2-methylpyrrole (Cornforth & Firth, 1958), led to a procedure (Cessi, 1952; Cessi & Piliego, 1960) by which unsubstituted amino sugars can be differentiated from their 3-derivatives, as Johansen, Marshall & Neuberger (1960) pointed out. This paper deals with the estimation of Dgalactosamine in the presence of D-glucosamine, a problem also studied by Tracey (1955) and other workers. The mechanism of the Elson-Morgan reaction is still obscure. Cornforth & Firth (1958) suggested that an intermediate (I):