Lin Yang,Yijing Ai,Shihui Xu,Lisi Wang,Xiaoping Zhang,Wei Sun
In this paper, Bismuth/poly(3,4-ethylenedioxythiophene) (Bi/PEDOT) modified electrochemical modified electrodes were prepared by electrochemical deposition method, and the electrochemical performance of the electrode was investigated using cyclic voltammetry under the optimal experimental conditions. The PEDOT polymer has high conductivity, and bismuth can form an alloy with cadmium ions. Bi/PEDOT nanocomposite materials have a larger specific surface area and more active sites, which is more conducive to absorbing more cadmium ions (Cd 2+ ). The Differential pulse anodic stripping voltammetry method was used to study the electroanalytical performance of the sensor for Cd 2+ . The data show that the oxidation peak current of cadmium ions in the Bi/PEDOT modified electrode is significantly higher than that of other electrodes, due to the synergistic effect of the composite conductive materials. In the concentration range of 1 nM-40 μM, the concentration of cadmium ions shows a good linear relationship with the peak current, and the lowest detection limit is 0.33 nM. In addition, the sensor also exhibits good stability, reproducibility and very low detection limit, which can be used for rapid determination of trace cadmium ions, with a recovery rate in actual sample analysis of 101.4 %-104.0 %.
Yanyan Niu,Yuxue Chen,Xiaoping Zhang,Hui Xie,Guiling Luo,Wei Sun
In this paper a photoelectrochemical (PEC) aptasensor based on specific recognition between aptamer and target cadmium ion (Cd(II)) with change of the sensing interface structure was constructed. A ZnO-TiO 2 nanocomposites and Au nanochains (Au NCs) modified electrode as photosensitive substrate was prepared and further covalently bound with graphite-like carbon nitride (g-C 3 N 4 ) on the free end of the aptamers to amplify the detection signal, which was applied to Cd(II) detection. Graphite-like carbon nitride with narrow band gap exhibited unique photoelectric property under UV and visible light irradiation. When the target Cd(II) was detected by the modified interface of the aptasensor, the structure of sensing interface was changed with the signal sensitizer g-C 3 N 4 closed to the interface, which caused the changes of photocurrent signal more sensitive and exhibited a good linear relationship with the Cd(II) concentration, so as to realize the quantitative analysis of the target. This PEC aptasensor showed a high sensitivity with a detection limit as 1.1 × 10 −11 mol/L and was further applied to the water sample detection successfully.
危险品化学品经营许可证（带存储）