Electrocatalytic oxidation and amperometric determination of sulfasalazine using bimetal oxide nanoparticles-decorated graphene oxide composite modified glassy carbon electrode at neutral pH

Cube-shaped samarium orthovanadate (SmVO₄) nanoparticles were interconnected with a graphene oxide sheet (GOS) using a simple and eco-friendly method to generate a SmVO₄@GOS nanocomposite. SmVO₄ was characterized using various spectroscopic and microscopic techniques, which confirmed the wrapping of GOS around the SmVO₄ nanoparticles. SmVO₄@GOS was then used to modify a glassy carbon electrode (GCE), which was evaluated for its electrochemical performance toward the assay of sulfasalazine (SSZ), an antibiotic drug. Cyclic voltammetry and amperometry were both used for the assay of SSZ using the SmVO₄@GOS-modified GCE at pH 7. The modified amperometric sensor is more sensitive, with a low detection limit (2.16 nM) and wide linear range of 20 nM-667 μM (Ag/AgCl). The electrochemical oxidation of SSZ was tested with blood serum and urine samples at physiological pH with recoveries in the range 96.1-98.6%. It indicates that the modified electrochemical sensor has good sensitivity and practical applicability toward SSZ detection. In the field of non-enzymatic sensors, SmVO₄@GOS/GCE provides a highly promising performance. Therefore, the electrochemical sensors have capacity for extensive analytical applications in biomedical devices.