Photochemical procedure used in South Africa for automated photometric determination of dissolved carbon in seawater

Abstract

A method for the simultaneous determination of total dissolved carbon and dissolved inorganic carbon in a single sample of seawater is described. This method allows the indirect determination of the organic carbon concentration without a preliminary purging step. Low power, far-ultraviolet photochemical digestion of the sample in alkaline medium is employed for the determination of total dissolved carbon. The carbon dioxide generated from the total carbon present is dialyzed through a silicone-rubber, gas-permeable membrane and reacted with a weakly buffered phenolphthalein indicator. The decrease in colour of the indicator is proportional to the carbon concentration. Any interfering chlorine developed from the chloride present in the seawater is removed by complexing with a 1,0M solution of hydroxylamine hydrochloride after the sample emerges from the digestor. © 1983 Taylor & Francis Group, LLC.