A sensitive electrochemical sensor based on Ag NPs decorated on magneticgraphene composite towards pethidine and morphine analysis

During last decade, electrochemical methods like voltammetric determination have been applied for measuring of different species in environmental and biological samples [۱]. These methods have several benefits such as low-cost, superior sensitivity and selectivity [۲, ۳]. The present work focuses on the design of a novel electrochemical platform based on Ag nanoparticles decorated onmagnetic graphene composite modified glassy carbon electrode (Ag@MG/GCE) for simultaneousdetermination of pethidine and morphine in the biological fluids. The as-synthesized Ag@MGnanocomposites was characterized by various methods such as X-ray diffraction (XRD), energydispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FE-SEM), and Fourier transform infrared (FT-IR). The electrooxidation of pethidine in presence of morphine was also investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. In order to investigate the electrode charge-transfer resistances, electrochemical featuresof the modified electrode was studied via electrochemical impedance spectroscopy (EIS) analysis.Based on the experimental results, wide linear range was observed over ۰.۱ to ۸۰۰ μM for bothanalytes with detection limits of ۰.۰۵ and ۰.۰۷۵ μM for pethidine and morphine, respectively.Finally, the Ag@MG/GCE with high sensitivity, selectivity and repeatability was successfully used for analysis of pethidine and morphine in biological samples.