title: Direct determination of chemical oxygen demand by anodic decomposition of organic compounds at a diamond electrode.
abstract: Chemical oxygen demand (COD) was measured directly with a simple electrochemical method using a boron-doped diamond (BDD) electrode. By applying a highly positive potential (+2.5 V vs Ag/AgCl) to an aqueous electrolyte containing potassium hydrogen phthalate, glucose, and lactic acid or sodium dodecylbenzenesulfonate using a BDD electrode, an anodic current corresponding to the electrolytic decomposition of these organic compounds was observed. No such current was seen on glassy carbon or platinum electrodes due to a significant background current caused by the oxygen evolution reaction. The electric charge for the anodic current observed at the BDD electrode was found to be consistent with the theoretical charge required for the electrolytic decomposition of the organic compounds to CO2 and was used to calculate COD. This analysis was performed by a simple I-t measurement at constant potential using a BDD electrode, and no calibration was needed. This new simple indicator, "ECOD" (electrochemical oxygen demand), will be useful for continuous monitoring of industrial wastewater with low protein concentrations and on-site instant analysis of natural water with a BDD electrode-based portable ECOD meter.
authors: Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science , 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
authors: Takeshi
authors: T
authors: Kondo
authors: Yusuke
authors: Y
authors: Tamura
authors: Masaki
authors: M
authors: Hoshino
authors: Takeshi
authors: T
authors: Watanabe
authors: Tatsuo
authors: T
authors: Aikawa
authors: Makoto
authors: M
authors: Yuasa
authors: Yasuaki
authors: Y
authors: Einaga