A simple gold plate electrode modified with Gd-doped TiO_2 nanoparticles used for determination of trace nitrite in cured food

摘要

A simple gold plate electrode (GPE) based on a gadolinium-doped titanium dioxide (Gd/TiCy ultrathin film was successfully constructed by using a surface sol-gel technique, and used for the detection of trace amounts of nitrite in cured foods. The Gd/TiCO_2 nanoparticles were synthesised and characterised via scanning electron microscopy (SEM) and X-ray diffraction (XRD), indicating that the Gd-doped TiO_2 formed an anatase phase through roasting at 450℃, generating actively interstitial oxygen at the interface of the surface of TiO_2 lattice surrounded by Gd~(3+). The electro-catalytic effect for oxidation of nitrite on the modified electrode was investigated by cyclic voltammetry in O.lOmoll~(-1) sulfuric acid media solution, showing that the modified electrode exhibited excellent response performance to nitrite with good reproducibility, selectivity and stability. The catalytic peak current was found to be linear with nitrite concentrations in the range of 8.0 × 10~(-7) to 4.0 × 10~(-4) moll~(-1), with a detection limit of 5.0 × 10~(-7) moll~(-1) (S/N=3). The modified electrode could be used for the determination of nitrite in the cured sausage samples with a satisfactory recovery in the range of 95.5-104％, showing its promising application for food safety monitoring.