Simultaneous Determination of Nitrite and Ascorbic Acid in Fruits and Vegetables by Differential Pulse Voltammetry

Hydroquinone (HQ) was used to catalyze Methanobactin (Mb) to reduce chlorauric acid to prepare Gold Nanoparticles (AuNPs). Mb@AuNPs was modified onto the surface of a bare gold electrode via electrodeposition to prepare the Mb@AuNPs/Au electrode. Subsequently, differential pulse voltammetry was conducted for the simultaneous determination of nitrite and ascorbic acid concentrations as well as condition optimization. For the electrode assembly, electrodeposition was performed with a 0.20 mol/L and pH6.5 PBS at a 100 mV/s scan rate for 40 cycles. In the linear range of 2~5600 μmol/L and 1~6000 μmol/L, the oxidation peak current of both nitrite and ascorbic acid detected by Mb@AuNPs/Au showed a good linear relationship with the concentration (R²>0.9928), and the limit of detection (LOD) was 0.31 and 0.57 μmol/L, respectively. The recovery rates of standard addition for the actual samples were 92.59%~109.26%, 90.01%~103.51%. The method has good reproducibility and stability and can be used for simultaneous determination of nitrite and ascorbic acid in fruits and vegetables.