Appraisal of the Iodate–Sulphuric Acid Wet-Oxidation Procedure for the Estimation of the Caloric Content of Marine Sediments

Abstract

Endothermic reactions of the inorganic fraction of marine sediments and the low organic matter content invalidate the determination of caloric values by bomb calorimetry. However, oxidation of the organic fraction with excess potassium iodate and back titration with sodium thiosulphate provides a suitable method for estimating the caloric value.Contrary to earlier reports, a correction factor for the incomplete combustion of proteins, derived from the Kjeldahl nitrogen content of the sample, must be applied. Interference by the inorganic fraction of the sediment in the titration procedure is allowed for by a control flask containing a sample of the sediment from which the organic matter has been removed by heating in a muffle furnace. Any ferrous sulphide in the sample is oxidized prior to digestion.