BIFUNCTIONAL CRYPTAND MODIFIER FOR CAPILLARY ELECTROPHORESIS IN SEPARATIONS OF INORGANIC ORGANIC ANIONS AND INORGANIC CATIONS/

The macrocyclic polyether cryptand-22 was employed as a bifunctional m odifier to separate cations and anions via capillary electrophoresis, The remarkable cation complexing ability of cryptand-22 resulted in an improvement in the separation/resolution of several cations, e.g., K, Na+ and NH4+ ions, by capillary electrophoresis. Cryptand-22 was pro tonated as cryptand-2H(2+) at pH < 7 and the protonated cryptand-22 wa s used as a capillary surface modifier to separate various organic/ino rganic anions by capillary electrophoresis, This modifier treatment re sulted in the electro-osmotic flow (EOF) and electrophoretic mobility of the anions being in the same direction, thereby giving a greater co lumn efficiency, At pH < 7, cryptand-22 is protonated and its behaviou r is similar to that of quaternary ammonium salts which can form compl exes with anions; in addition, the EOF is reversed, The effect of the eluent anion on the velocity of the EOF was also investigated; the max imum velocity of the EOF was obtained by using acetic acid as the elue nt, The capillary electrophoresis system with the protonated cryptand modifier was successfully applied to the separation and determination of various inorganic anions, e.g., I-, NO3-, SCN-, BrO3-, IO3- and CrO 42-, and various carboxylate anions, e.g., p-nitrobenzoic acid, p-chlo robenzoic acid, p-hydroxybenzoic acid, benzoic acid and terephthalic a cid.