Comparison of Methods for Determination of Organic Carbon in Marine Sediment

Assessment of two methods for the determination of organic carbon (OC) in the silt-clay fraction of marine sediment has been carried out with reference to values from the decarbonated sediment, using a CHN analyzer. Although the mass loss on ignition (MLOI) was lower at 440°C than at 550°C or 600°C, the OC contents were overestimated by a factor near three from these results, and the rank order of OC in different sediments was not reproduced. Wet oxidation using the revised Walkley–Black titration overestimated OC in anoxic sediments, but gave an underestimation for oxic sediment. The need for sediment reference material with certified OC content is stressed.