A fully automated method for the determination of chemical oxygen demand

Abstract

A novel approach to the determination of chemical oxygen demand based on the use of a porous catalytic silver electrode is described. The conditions used in the digestion step are essentially the same as for the standard method, but the amount of oxidant (dichromate or permanganate) consumed is determined by allowing the excess of oxidant to react with hydrogen peroxide to liberate oxygen, which is measured coulometrically by the electrochemical sensor. The effectiveness of the present automated method as a detector of organic pollution is assessed by studying the oxygen absorbed values of synthetic sample solutions of several pure organic compounds. Percentage oxidation values are calculated and compared with those obtained with standard methods. Various aspects of interferences and their removal are also discussed.