Visible light photoelectrochemical sensor for determination of progesterone based on polydopamine/quantum dots nanocomposites

In photoelectrochemical (PEC) detection process, light is used as the excitation source and photocurrent is obtained as the detection signal. Therefore, it can exhibitscharge-transfer upon photoexcitation and achieves the detection purpose via the intensity of the photocurrent. In this study, polydopamine/CdS quantum dots (QDs) nanocomposite was deposited on Ti sheet as semiconductor to make a PEC sensor.The CdS QDs were electro-synthesized on Ti sheet which followed by chemically deposition of polydopamine (PDA). The as-prepared PDA/CdS QDs/Ti displayed much higher photocatalytic activity than the CdS QDs/Ti and PDA/Ti, which was attributed to the synergic effect between CdS QDs and PDA, which included the optical property, the better dispersion and the small size. Thus, it was applied as a PEC sensor under the visible light for determination of progesterone. Results show that the best response is obtained in acetate buffer solution (pH=5) as a supporting electrolyte at applied potential of 2 V vs. Ag/AgCl reference electrode. Also the photocurrent intensity increased with increasing concentration of progesterone ranging from 2 nM to 2ᵡ104 nM. The detection limit was obtained 1.54 nM and the RSD was 3.77 ℅.