APPLICATION OF CAPILLARY ELECTROPHORESIS FOR THE DETERMINATION OF DISSOLVED-GASES IN WATER SAMPLES - I - DETERMINATION OF DISSOLVED-OXYGEN

The determination of dissolved oxygen in water samples was performed b y capillary electrophoresis. This was based on the oxidation of pyroga llol in alkaline media by dissolved oxygen. The oxygen sample was inje cted into the capillary electrophoresis system consisting of phosphate buffer at pH 5.6 and 0.5 M pyrogallol. Electrophoretic mixing of samp le and reagent was achieved during the electrophoretic run and the rea ction product was monitored at 440 nm. The assay procedure was optimiz ed with respect to the carrier electrolyte concentration and pH, pyrog allol concentration, sample pH, and modes of operation of the applied voltage. As little as 20 ppb of the dissolved oxygen could be determin ed by the proposed method within 10 min. The method was successfully a pplied for the determination of dissolved oxygen in river and drinking water. (C) 1997 Elsevier Science B.V.