Electro oxidation and analytical applications of nimesulide at graphene oxide and reduced graphene oxide modified carbon paste electrode

Electrochemical analysis of bio-active drug nimesulide (NIM) has been examined at carbon paste electrode using modifiers graphene oxide and reduced form of graphene oxide modified (GO/CPE & rGO/CPE) by voltammetry techniques. Effect of various parameters pH, concentrations, varying scan rates, and interfering agents were considered. Linear relation between peak potential, peaks current, scan rate, temperature, heterogeneous constant, concentration variation was attained. Different voltammetric techniques were utilized to study the application part of the proposed sensors, such as differential pulse voltammetry (DPV) and square wave voltammetry (SWV). The linear response was observed in the range of 300 to 0.1nM with a detection limit of 11.20 nM (DPV) 1.08 nM (SWV) at GO/CPE and 1.03 nM (DPV) and 0.1nM (SWV) at rGO/CPE. A probable mechanism of electrochemical oxidation of NIM was proposed, and activation parameters such as E-a = 21.12 kJ mol(-1), Delta H-not equal = 18.64 kJ mol(-1), Delta S-not equal = -299.7 J K(-1)mol(-1) and Delta G(not equal)= 70.67 kJ mol(-1), were determined. (C) 2019 Elsevier Ltd. All rights reserved.