PURPOSE: To obtain a novel cation exchanger for liquid chromatography by incorporating boric acid and/or its salt as a complex form in a hydroxyl group- contg. matrix.

CONSTITUTION: Comlexed boric acid is used as a cation exchanger for liquid chromatography in a hydroxyl group-contg. matrix. And, the cation exchanger is used to separate a cationic substance by ion exchange chromatography. Wherein, by using complexed boric acid as a stationary phase, a diol content in the stationary phase is obtained. Further, the hydroxyl group-contg. stationary phase is treated with a boric acid-contg. soln.