CRYSTALLIZATION OF ORGANIC-CRYSTALS WITH TAILOR-MADE INHIBITORS - DETERMINATION OF L-LYSINE USING L-GLUTAMIC ACID AS SUBSTRATE

A very simple turbidimetric procedure is used for determination of L-l ysine, based on its inhibitory action on the crystallization of L-glut amic acid. The obtention of supersaturated solutions of L-glutamic aci d was accomplished by means of the change in the solvent composition. Thus, the addition of ethanol to stable aqueous solutions of this amin o acid allows the obtainment of unstable supersaturated solutions. The method suffers from very few interferences and permits the developmen t of an analytical procedure to determine L-lysine in the presence of D-lysine. The method was also applied to the determination of L-lysine in pharmaceutical products.