Design of an electrochemical platform for the determination of diclofenac sodium utilizing a graphenized pencil graphite electrode modified with a Cu–Al layered double hydroxide/chicken feet yellow membrane

Abstract

A novel electrochemical sensor based on a Cu–Al layered double hydroxide (Cu–Al LDH)/chicken feet yellow membrane (CFYM) modified graphenized pencil graphite electrode (GPGE) was designed. The present modified electrode provides a simple voltammetric method for the sensitive detection of diclofenac (DCF) for the first time. In the first stage, a one-step potentiostatic method was utilized for the in situ synthesis of graphene oxide directly on the PGE surface in H₂SO₄ solution under optimized conditions. Then certain values of Cu–Al LDH (synthesized via a co-precipitation method), and CFYM dispersion in dimethylformamide was homogenized by sonication for 60 min. Finally, 10 μL of resulting dispersion was drop-cast on the surface of the GPGE. The structure and morphology of the surface of the modified electrode were characterized using SEM and XRD techniques. Compared with the unmodified pencil graphite electrode, the Cu–Al LDH/CFYM/GPGE modified electrode showed an enhanced electrochemical response toward DCF oxidation using cyclic voltammetry (CV) and differential pulse voltammetric (DPV) techniques. The effect of parameters such as the scan rate and pH value on the peak current was studied. Under the optimized conditions, the Cu–Al LDH/CFYM/GPGE showed a linear current response for the oxidation of DCF in the range of 1.99–23.44 μM. The sensitivity, limit of detection (LOD), and limit of quantification (LOQ) of the proposed sensor for the detection of the DCF were calculated to be 6.02 μA μM⁻¹, 1.91 μM, and 6.39 μM, respectively. Moreover, the modified electrode was successfully examined for the detection of DCF in real samples.