Static and dynamic analysis of sulfamethoxazole using GO/ZnO modified glassy carbon electrode by differential pulse voltammetry and amperometry techniques.

Surface water contamination of sulfamethoxazole (SMX) has tremendously affected the ecosystem. A primary study was performed to develop an electrochemical sensor for the determination of SMX. Overcoming the demerit associated with the conventional techniques, an electrochemical method was developed using GO/ZnO nanocomposite modified electrode to detect SMX in 0.1 M phosphate buffer (pH-5.5) buffer solution. The GO, ZnO and GO/ZnO nanocomposite were prepared using modified Hummer's, precipitation and sonochemical methods, respectively. Physico-chemical properties of all the materials and its modified electrode were analysed. Comparison was made by studying the SMX sensing performance of electrodes modified with GO, ZnO and GO/ZnO nanocomposites. Out of which GO/ZnO nanocomposite exhibited excellent sensing performance with the concentration range from 0.10 × 10 to 1.5 × 10 M with the limit of detection (LOD) 28.9 nM. The parameters such as electrolyte, effect of pH, scan rate were optimized for effective sensing performance. From the optimized results 0.1 M phosphate buffer was found to be a suitable electrolyte and the pH 5.5 was found to be appropriate to sense SMX at the scan rate 50 mVs. Under optimized condition, the Differential Pulse Voltammetry (DPV) and Amperometry techniques were adopted for electrochemical sensing of SMX under static and hydrodynamic condition. The developed method was successfully tested for real time analysis for the samples collected from waste water treatment plant.