Electrochemical sensor for urea determination using structural c-multiwall carbon nanotubes decorated CuO hybrid nanocomposite: Application in rice water samples

The modified electrochemical sensor using copper oxide nanoparticles (CuO NPs) modified Glassy Carbon Electrode (GCE) (CuO NPs/GCE) and Copper Oxide/c-Multiwall carbon nanotube nanocomposite modified GCE (CuO/c-MWCNT/GCE) are used for determination of urea. The crystallite size of CuO NPs and CuO/c-MWCNT structured nanocomposite is 30.06 nm and 57.94 nm respectively. Due to the presence of oxygen functionalities on the surface of CuO NPs found to exhibit decreasing crystallite size and aggregated form of CuO/c-MWCNT nanocomposite in which presence of CNT on surface made the impact towards increased crystallite size. In this research work, the electrochemical sensing of urea was performed using squarewave voltammetry (SWV) and cyclic voltammetry (CV). The urea detection was examined using SWV signals at potential range −0.4 to + 0.4 V (vs. Ag/AgCl) in rice water samples using CuO NPs/GCE and CuO/c-MWCNT/GCE electrode system. The different urea concentrations were analyzed in wide linear ranges of 2 mM–8 mM with limit of detection(LOD) 0.26 mM/L and 0.16 mM/L respectively. The indepth discussion about developed electrodes towards the urea detection seems to exhibit its own characteristics that are not explored previously. Thus CuO/GCE and CuO/c-MWCNT/GCE offerings on structural sensitivity are analyzed for repeatability in real-time analysis using rice water samples.