Abstract: An automated total organic carbon analyzer is described. Embodiments of the system include two features, namely the development of a selective oxidation reactor to oxidize organic contaminants to their corresponding organic acids, and the measurement of the organic acids individually by chain length using an electroanalytical detector. Combining this electroanalytical approach with sequential detection capabilities (such as spectrophotometry) can expand the instrument capabilities by providing organic contaminant speciation. The described reactor performs selective oxidation of organic carbon to organic acids followed by complexation with a proprietary ligand, then selective detection using electroanalytical accumulation and desorption of organic acids performed at an electrode surface.