Simultaneous capillary electrophoretic separation of small anions and cations after complexation with ethylenediaminetetraacetic acid

A new approach for simultaneous separation of small inorganic and organic a nions and metal cations by capillary electrophoresis is demonstrated. Metal cations in the sample are transformed into their chelates with EDTA and ar e separated together with the anions using an anionic separation mode. Simu ltaneous separation of 19 common anions and cations was achieved in about 6 min with the electrolyte containing 5 mM K2CrO4, 3 mM boric acid, 35 mu M cetyltrimethylammonium bromide and 12 mu M EDTA at pH 8. Limits of detectio n (s/n=3) were in the range from 4 ppb for Cl- up to 1250 ppb for Cu-EDTA a nd RSDs of peak areas ranged from 1.4% for Cl- up to 8.5% for Mn-EDTA chela te. The practical applicability of the method was demonstrated on the analy sis of anions and cations in various water samples. (C) 1999 Elsevier Scien ce B.V. All rights reserved.