ELECTROPHORETICALLY MEDIATED MICROANALYSIS OF CALCIUM

Electrophetically mediated microanalysis (EMMA) was used for the deter mination of calcium. The faster analyte zone containing the calcium wa s injected spatially behind a slower zone of o-cresolphthalein complex one in a capillary electrophoresis based system. Upon application of t he electric field the calcium zone was electrophoretically mixed with the reagent and product was formed. The bulk electroosmotic flow carri ed the product to the detector where the absorbance of the resulting c omplex at 575 nm was measured. Quantitation using an internal standard yielded a linear response with an R.S.D. of 8.1%. An inter-method com parison was performed with the standard bulk method and yielded result s that did not significantly differ. The advantages of EMMA with respe ct to traditional methods were addressed.