DETERMINATION OF METAL-IONS BY CAPILLARY ZONE ELECTROPHORESIS WITH ON-COLUMN CHELATION USING 8-HYDROXYQUINOLINE-5-SULFONIC ACID

A novel method of separating and detecting metal cations by capillary zone electrophoresis is described. 8-Hydroxyquinoline-5-sulfonic acid (HQS-) is added to the mobile phase, so that metal HQS complexes are formed within the capillary. These complexes can be selectively and sensitively detected by using laser-based fluorometry. Furthermore, by controlling mobile-phase parameters which affect the complexation reaction, the observed electrophoretic mobility of the metal can be manipulated. The utility of this method for metal analysis is investigated with three test ions: Ca(II), Mg(II), and Zn(II). Limits of detection in the parts per billion range are achieved, and a model for predicting the mobility of the band is tested. The technique is applied to the detection of Ca(II) and Mg(II) in blood serum.