Study on Molecularly Imprinted Sensor Based on Photocurrent Response for Ni-complex

A novel molecularly imprinted sensor based on photocurrent was fabricated to detect Ni2+. CdTe quantum dots (QDs) were selected as photoelectric material and modified on an indium-tin oxide (ITO) electrode, then the nickel-1-(2-pyridylazo)-2-naphthol molecularly imprinted film was formed on the QDs layer by photopolymerization. While 365 nm ultraviolet light was used as the excitation light, an electron-hole pair could be generated by the QDs. The electron receptor ascorbic acid would form a photocurrent under the excitation of the electron as detection signals. Ni2+ was determined according to “gate-effect”. The complex was characterized by Fourier transform infrared spectrum and the CdTe QDs were characterized by ultraviolet absorption spectrum and fluorescence emission spectrum. The time for elution and rebinding, as well as the concentration of ascorbic acid, were also optimized. The experimental results indicated that there was a liner relationship between the photocurrent and the concentrations of Ni2+ in the range of 5 × 10−11 − 5 × 10−8 M, with a detection limit of 8.31 × 10−12 M. The sensor had good selectivity, and was applied in real water samples analysis.

Graphical AbstractWhen the Ni-PAN complex was removed, the embedded CdTe QDs were excited by 365nm UV-light through imprinted cavities and photocurrent was generated. With the increase of Ni2+ concentration, photocurrent decreased. The signal-to noise ratio and sensitivity were greatly improved due to the avoiding of the electrical excitation.Figure optionsDownload as PowerPoint slide