Construction of Dawson-Type Molybdovanadophosphoric Acid-Based Electrochemical Sensor and Its Application in Sensing Folic Acid

In current work, vanidium-substituted polyoxometalate clusters H8P2Mo16V2O62 and carbon nanotubes (CNTs)@Au NPs were incorporated into a multilayer composite film via combining layer-by-layer self-assembly. The result showed that the incorporation of the three kinds of active components would improve the electrocatalytic activity to the oxidation of FA and electron transfer rate greatly. In 0.2 M phosphate buffer solution (pH = 7.35), the composite film (PEI/P2Mo16V2/PEI/CNTs@Au)2 had a linear range of FA from 4.99 × 10-7 M to 1.29 × 10-5 M and 1.29 × 10-5 M to 1.21 × 10-3 M, and a limit of detection to be 3.96 × 10-8 M (S/N = 3). In addition, the composite film has an excellent anti-interference property to potential co-exist interfering species like inorganic ions and biomolecules (including NaCl, K2CO3, NH4Cl, NaNO2, Na2SO4, fructose, L-glutamate and glucose). The developed sensor has a good working and long-term stability as well. Besides, the sensor was applied in detecting FA in vitamin b tablet, the recoveries were all in the allowable error range. (This paper is funded by the International Exchange Program of Harbin Engineering University for Innovation-oriented Talents Cultivation.) Figure 1