The electrochemical behaviors and kinetics of AuNPs/N, S-GQDs composite electrode: A novel label-free amplified BPA aptasensor with extreme sensitivity and selectivity

Abstract

A highly sensitive electrochemical sensor was developed for the determination of Bisphenol A (BPA) by immobilizing the aptamer on the glassy carbon electrode which was modified by nitrogen-sulfur-doped graphene quantum dots (N, S-GQDs) and Au nanoparticles. We mainly delved into the density of states of N, S-GQDs and the detection mechanism of sensor. On the basis of the improved detector, we focused on the research of kinetic parameters, such as the activation surface area (A), electron transfer coefficient (α), the standard rate constant (k), diffusion coefficient (D), and surface concentration (Г0). Under the optimal conditions, the DPV response of the sensor to BPA was a linear detection range from 0.1 to 10 μM and the detection limit was around 0.03 μM. It was noted that the developed sensor was excellently suitable for measuring BPA in tap water, and the recovery ranged from 82.6 to 107%.