An Automated Batch-wise Flow System for Determination of Reactive Copper in Water Samples

Abstract

A new type of flow system was proposed for the determination of reactive copper in water samples. The reactive copper was determined by spectrophotometric monitoring of the copper-catalyzed aerial oxidation of L-ascorbic acid to dehydroascorbic acid (DAA) and the formation of quinoxaline derivatives (QX) by the reaction of DAA with o-phenylenediamine. Absorbance of QX at 340 nm was measured after a reaction time of 5 min at 35oC. Considerable adsorption loss of copper was found for PTFE tube of a continuous flow FIA system. It was minimized by the proposed automated batch-wise flow system with individual injection lines for sample and reagent solutions and a cell for reaction and absorbance measurement. A linear calibration curve of copper up to 20 μg/l was obtained by the addition of Al (and F) ions as adsorption inhibitor. The usefulness of the proposed system was demonstrated in the determination of reactive copper in artificial water samples.