Nanodiamond Decorated with Silver Nanoparticles as a Sensitive Film Modifier in a Jeweled Electrochemical Sensor: Application to Voltammetric Determination of Thioridazine

摘要

Nanodiamond-graphite (NDG) decorated with Ag nanoparticles (AgNPs-NDG) was prepared and used to construct a novel sensitive sensor for the voltammetric determination of thioridazine (TR). The results indicate a remarkable increase in the oxidation peak currents together with a negative shift in the oxidation peak potentials, in comparison to the bare pyrolytic graphite electrode. Remarkable enhancement in microscopic area of the electrode along with strong adsorption of TR on the surface of the modified electrode resulted in a considerable increase in the peak current of TR. The surface morphology and the nature of the composite film deposited on PGE were characterized by scanning electron microscopy, atomic force microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Experimental variables, such as the deposited amount of the modifier suspension, pH of the supporting electrolyte, the accumulation potential and time are optimized by monitoring the CV responses of TR. Under the optimal conditions, the modified electrode showed a wide linear response to the concentration of TR in the range of 0.08-100μM with a detection limit of 0.01μM. The prepared modified electrode showed several advantages: simple preparation method, high stability and uniformity in the composite film, high sensitivity, long-term stability and remarkable voltammetric reproducibility in response to TR. The modified electrode can be successfully applied for accurate determination of trace amounts of TR in pharmaceutical and clinical preparations.