Highly sensitive and selective serotonin sensor based on gamma ray irradiated tungsten trioxide nanoparticles

This work investigates the sensitive and selective electrochemical method for determining serotonin (5-HT) using gamma ray irradiated tungsten trioxide (GI-WO3) nanoparticles. WO3 NPs synthesized by microwave irradiation method was subjected to gamma ray irradiation under different doses (0-150 kGy) and the products were characterized by powder XRD, HRTEM, Raman and UV-vis spectra. The experimental results demonstrated that the 100 kGy irradiation on WO3 NPs led to significant changes in morphology, crystal structure and improvement in specific surface area and fast electron transfer rate which enhanced its electrocatalytic activity greatly. Cyclic voltammetry and differential pulse voltammetry studies of GI-WO3 NPs modified glassy carbon electrodes (GCE) exhibited improved electrocatalytic activity towards the oxidation of 5-HT in a phosphate buffer solution (PBS, pH 7.0). The kinetic parameters such as diffusion coefficient, electron transfer coefficient and heterogeneous electron transfer rate constant involved in the oxidation of 5-HT at the 100 kGy GI-WO3/GCE indicate the suitability of the fabricated electrode for the detection of 5-HT. Under the optimized conditions, the oxidation peak currents were linearly proportional to 5-HT concentration over a wide linear range of 0.01-600 M, with the lowest detection limit of 1.42 nM (S/N = 3). The fabricated 5-HT sensor showed an excellent anti-interference ability against potentially coexisting electroactive species, long-term high stability and excellent reproducibility. The proposed sensor was successfully implemented for the determination of 5-HT in human blood serum samples with good recoveries ranging from 99.2% and 102.9%. (C) 2016 Elsevier B.V. All rights reserved.