Amperometric detection of nitrite based on Dawson-type vanodotungstophosphate and carbon nanotubes.

A nitrite sensor based on Dawson vanodotungstophosphates α2-K7P2VW17O62·18H2O (P2W17V) and carbon nanotubes (CNTs) was prepared by electrostatic layer-by-layer self-assembly technique. The sensor {PEI/PSS/[PDDA/P2W17V-CNTs]n} was characterized by UV-vis spectroscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray photoelectron spectra (XPS). The electron transfer and sensing ability of this sensor were explored using cyclic voltammetry (CV) and electrochemical impedance spectra (EIS) technology. The results show that the incorporation of CNTs and P2W17V into the composite film endowed the modified electrode with fast transfer rate and high electrocatalytic activity towards oxidation of nitrite. This nitrite sensor with 10 bilayers has a broad linear range of 5×10(-8) to 2.13×10(-3)M, a low detection limit of 0.0367μM (SN(-1)=3), a high sensitivity of 0.35mA mM(-1) NO2(-), an excellent anti-interference property in the presence of other potential interfering species and a good stable. It was successfully employed for determination of nitrite in real towards.