A novel and facile electrochemical synthesis of WO3 nanoparticles on the surface of glassy carbon electrode and their enhanced electrocatalytic performance in sensing of isoniazid

This work introducesa novel electrochemical approach to synthesize the tungsten oxide nanoparticles (WO3 NPs) on the GCE surfaceas an effective electocatalyst for isoniazidsensor.Stable WO3NPs havebeen prepared by a two-step electrochemical method. At first, thetungsten nanoparticles(W NPs) were electrodeposited on the GCE by potentiostaticmethod performedina criterion concentration of tungsten electrolytes(Na2WO4·2H2O, pH=7.0) at -1.3 V (vs. SCE) for 120 s, and then W NPs were oxidized to WO3 film via repetitive potential cyclingbetween -1.0V and 1.0 V at a scan rate of 100 mV/s in alkaline solution (0.1 M NaOH).The nanoparticles have been characterized in detail by field emission scanning electron microscopy(FESEM), energy-dispersive X-ray analysis(EDS) and X-raydiffraction (XRD)technique, indicatingthat the W and WO3 NPs have been successfully synthesized. The obtainedWO3/GCEsensor displays a significant enhancement of electrochemical activitytowards isoniazid. In addition, the electrochemical response of WO3/GCE is not influenced by potential interferents (ascorbic and uric acids, glucose, and various inorganic salts).Therefore, the proposed sensor was successfully used foranalysis of isoniazid in biological and pharmaceutical samples.The major important features of this sensor are its low cost, availability, simple and fast fabrication, reversible change of conductivity, increased surface-to-volume ratio,high stability, sensitivity, selectivity and biocompatibility which make it as a promising candidate to design a rapid and low-cost platform for (bio)sensorand catalyst applications.