LAUSR

A p-type transition metal dichalcogenide (WS2) was synthesized and hybridized with graphene oxide via a simple hydrothermal method. The as-prepared material was used to modify a glassy carbon electrode for the fabrication of a simple, stable, and repeatable methylene blue-labeled “signal-off” aptasensor used for the sensitive determination of very low amounts of sodium diclofenac (DCF). The synthetic material, modification process, and role of WS2 in the current response enhancement were studied by X-ray diffraction, energydispersive X-ray spectroscopy, field emission scanning electron microscopy, high resolution transmission electron microscopy, Hall effect, cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Subsequently, a wide linear range of DCF concentration (0.5–300 nmol/L), very low limit of detection (0.23 nmol/L), and good selectivity were obtained using the differential pulse voltammetry method with the assembled aptasensor. Finally, the fabricated aptasensor was successfully developed for physiological real samples with significant recoveries.