Catalytic determination of dissolved inorganic carbon in natural waters by flow injection spectrophotometry

Abstract

A flow injection procedure for the spectrophotometric determination of inorganic dissolved carbon in natural waters is described. The method is based on the ability of the hydrogencarbonate anion to catalyse the slow reaction of EDTA with Cr^III ions of an aged aqueous solution. The proposed system handles up to 36 samples per hour with hydrogencarbonate contents ranging from 10 to 300 mg l^–1, with RSDs better than 1%. The results for waters agree well with those obtained by titration.