▎ 摘　　要

Gold nanoparticles (Au NPs) and graphene-doped CdS (GR-CdS) were employed to fabricate a photoelectrochemical (PEC) aptasensor for detection of diclofenac (DCF). It was observed that GR-CdS modified electrode exhibited a high and stable photocurrent response upon visible light illumination, due to the excellent electrical and optical property of GR as well as the high absorption efficiency of CdS in the visible region. While Au NPs were incorporated with GR-CdS, a further increase in photocurrent response was observed owing to surface plasmon resonance. Moreover, the Au NPs were advantageous to immobilize the SH-terminated aptamer used as a biorecognition element. Upon interaction of DCF with the immobilized aptamer, the DCF molecules were captured by the aptasensor. When the sensor was illuminated with visible light, an enhanced PEC current response to DCF was realized due to the oxidation of the captured DCF by the photogenerated holes. Under the optimized conditions, the sensor showed a PEC response linear to DCF concentration in the range of 1-150 nM, with a detection limit (3S/N) of 0.78 nM. Thus, a highly selective and sensitive PEC sensor for the determination of DCF was provided. (C) 2017 Elsevier B.V. All rights reserved.