A dry oxidation method for the analysis of the TOC in seawater

A high-temperature oxidation method is described for the accurate and precise determination of the total organic carbon (TOC) in seawater. Problems of contamination in sample storage, preparation, and oxidation which are evident in previous dry oxidation methods have been controlled. The TOC results from different areas are determined and compared directly with the results obtained on duplicate samples with the persulfate oxidation method. Significantly higher TOC values (15–20%) are obtained with the dry oxidation procedure, but the relative difference in the methods is relatively constant over depth and geographic areas. A high correlation between the methods was obtained. For accurate results, the dry method is recommended but conclusions based on profiles of TOC determined by either method should be similar if the proper precautions in analysis are followed.