Determination of chemical oxygen demand (COD) at boron-doped diamond (BDD) sensor by means of amperometric technique

摘要

A boron-doped diamond (BDD) sensor was proposed for effective detection of chemical oxygen demand (COD) by means of amperometric technique. Thin boron doped diamond active sensor layer was deposited on Si wafer and glassy carbon substrate by Microwave Plasma Enhanced Chemical Vapor Deposition (MW PE CVD). The structure of BDD was confirmed by Raman spectra analysis. Broad Raman bands centered at 482 cm~(-1) and 1219 cm"1 are typical for boron-doped diamond layers. The BDD deposition onto the glassy carbon gives the maximum oxygen reduction peak current with the lowest background signal. The reduction of O2 on boron-doped diamond electrode was studied in DMSO solution The reduction of oxygen at boron-doped diamond predominantly involves the le" reduction of oxygen to superoxide. The lowest COD detection limit was about 0.3 mg/1.