Highly sensitive determination of piroxicam using a glassy carbon electrode modified with silver nanoparticles dotted single walled carbon nanotubes-reduced graphene oxide nanocomposite

Herein, a glassy carbon electrode (GCE) modified with silver nanoparticles dotted single walled carbon nanotubes-reduced graphene oxide (AgNPs-SWCNTs-rGO) composite had been developed for highly sensitive determination of piroxicam. The synthesized nanocomposite was characterized by various techniques such as transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The morphology and microstructure characterizations revealed that Ag NPs with an average diameter of about 6 nm were well dispersed and attached on the surface of SWCNTs-rGO composite. The electrochemical characterization showed that AgNPs-SWCNTs-rGO composite modified electrode exhibited excellent electrocatalytic activity toward the oxidation of piroxicam. Under optimum conditions, the oxidation peak currents of piroxicam were linearly dependent on its concentrations in the range of 1.5-400 μM using linear sweep voltammograms (LSV), with detection limit of 0.5 μM. Linear responses versus piroxicam concentrations in the range of 0.05-250 μM was obtained using the chronoamperometry method, with detection limit of 0.5 nM. The proposed electrochemical sensor was also used for the determination of the analytes in real samples and gave satisfactory results, with recoveries in the range from 99.4 to 104%.