PURPOSE: To purify an aqueous solution of a dipeptide ester containing organic acids by supplying the solution to a treating chamber separated by an anion exchange membrane and a cation exchange membrane and treating under a specific condition, thereby easily removing the impurity organic acids in high efficiency.
CONSTITUTION: An aqueous solution of a dipeptide ester containing organic acids as impurities is supplied to a treating chamber separated from the other chambers of an electrolytic cell with an anion exchange membrane and a cation exchange membrane, brought into contact with an electrolytic solution interposing the anion exchange membrane therebetween and electrified with electrodes placed outside of the treating chamber while keeping the pH of the electrolytic solution to ≤7.0. The organic acids are removed from the treating chamber through the ion exchange membrane by this process. Preferably, the aqueous solution of dipeptide ester is α-L-aspartyl-L-phenylalanine methyl ester solution and its pH is 4.0-7.0.
HARADA TSUNEO
DOI MASAHARU
MORI TAKASHI
