Copper oxide nanosheet modified electrodes for simultaneous determination of environmentally hazardous anions

Electrocatalytic oxidation of sulphite and nitrite at copper oxide nanosheet (CuO-NS) modified glassy carbon electrode (GCE) under neutral condition was studied to assess the simultaneous electrochemical sensing ability of CuO-NS/GCE. The CuO-NS was prepared via a simple precipitation method. The structural and morphological evolution of the as synthesized CuO-NS was characterized with advanced tools and the existence of nanosheet morphology was ascertained. Using CuO-NS/GCE, the electrocatalytic oxidation of sulphite and nitrite was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. CuO-NS/GCE exhibited excellent electrocatalytic activity towards the oxidation of both sulphite and nitrite. The difference between the oxidation peak potential of sulphite and nitrite was similar to 400 mV. The sulphite sensitivity and limit of detection (LOD) were in the order of 4.02 mu Acm(-2) mM(-1) and 21.10 mu M, respectively. Similarly, the nitrite sensitivity and limit of detection (LOD) were in the order of 6.17 mu Acm(-2) mM(-1) and 13.6 mu M. Finally, application of CuO-NS/GCE sensor was demonstrated by the detection of nitrite and sulphite in different water samples with excellent recoveries. (C) 2018 Elsevier B.V. All rights reserved.