Preparation of capillary columns coated with linear polymer containing hydrophobic and charged groups for capillary electrochromatography

A linear polymer-coated capillary was prepared by in-capillary copolymeriza tion of N-tert-butylacrylamide (TBAAm) with a charged monomer, 2-aclylamido -2-methyl-1-propanesulfonic acid (AMPS), after the capillary pretreatment w ith a bifunctional reagent. The coated capillaries were applied in capillar y electrochromatographic (CEC) separation of small neutral compounds. Hydro phobic groups in the linear polymer, which were immobilized onto the capill ary surface, functioned as the stationary phase in reversed-phase CEC separ ation, and charged groups in the linear polymer generated electroosmotic fl ow (EOF) along the column. The coated capillaries were prepared by a simple procedure. Moreover, the reproducibility with respect to EOF rate and migr ation times of the solutes was excellent. The results for CEC separation of small molecules using the linear polymer-coated capillaries are presented.