A simple electrochemical biosensor based on HS-β-cyclodextrin coordination methanobactin/gold nanoparticles for highly sensitive detection of nitrite

Nitrite ( \(\mathrm{{NO}_2}^{-}\) ) is often added to food as a food additive, but the overuse of nitrite will pose a threat to human health, so it is important to establish a rapid detection method for nitrite in related food. In this work, gold nanoparticles (AuNPs) were synthesized by in situ reduction of methanobactin (Mb); it is a small bioactive peptide. HS-β-cyclodextrin (HS-β-CD) with supramolecular recognition function was coordinated with Mb/AuNPs by Au-S bond to form HS-β-CD@Mb/AuNPs. HS-β-CD@Mb/AuNPs were modified onto the surface of gold electrode by electrodeposition to successfully prepare the biosensor (HS-β-CD@Mb/AuNPs/Au). The HS-β-CD@Mb/AuNPs/Au was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), ultraviolet spectroscopy (UV), Fourier infrared spectroscopy (FTIR), fluorescence spectrometer (FL), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The established biosensor was successfully applied to the detection of nitrite in real samples, and the mechanism of NO 2 − oxidation was analyzed. The detection limit of the established detection system was as low as 0.013 μM in the linear range of 0.1–10,000 μM, the recoveries were 96.53–102.54%, and the selectivity of the sensor is demonstrated by anti-interference experiment. Also compared to the previously described electrochemical sensors, the newly developed ones have better sensitivity (50.7137 μA μM −1  cm −2 ) and selectivity. These results suggest that the work provides a new way for the accurate monitoring of nitrite in environmental and food safety.