An accurate, simple and novel analytical method for the determination of total organic carbon in sediment

An improvement to the Walkley-Black wet digestion method for accurate determination of total organic carbon (TOC) in mangrove and marine sediments was developed. Sediment samples were digested with acid dichromate in a domestic microwave for 7 minutes. The TOC results obtained from the proposed method were in excellent agreement with the conventional Walkley-Black method. The sediments were spiked with three standard organic compounds, at a fortification level (viz. 10 to 20 mg TOC). The mean recoveries of TOC for the proposed method ranged from 100 +/- 14% (n=15) for standard reference materials of marine/coastal sediments to 101 +/- 6% (n=30) for mangrove sediments. The relative standard deviation values of the proposed method were small, around 3 to 4%. These data demonstrate that the proposed method had a better performance than the conventional Walkley-Black method in terms of its simplicity, reproducibility, accuracy, precision and recovery.