A highly sensitive poly(chrysoidine G)-gold nanoparticle composite based nitrite sensor for food safety applications

This work demonstrated the development of conducting poly(chrysoidine G) (PCG)-gold nanoparticle (AuNP)-modified fluorine-doped tin oxide (F : SnO₂, FTO) film-coated glass electrodes for the sensitive electrochemical detection of nitrite (NO₂^-). The homogeneously distributed PCG nanoparticle layer was deposited onto the FTO electrode by cyclic voltammetry sweeping. AuNPs were then anchored onto the PCG/FTO electrode by the chemical reduction of pre-adsorbed Au³⁺ ions. The as-prepared AuNP/PCG/FTO electrode exhibited excellent electrocatalytic activity for the oxidation of NO₂^- with high sensitivity (approximately 0.63 μA cm^-2μM^-1) and a low limit of detection (0.095 μM), which is relevant within the normal concentration range of NO₂^- in human bodily fluids. The AuNP/PCG/FTO sensor showed sufficient reproducibility, repeatability, low interference, and strong recovery for NO₂^- detection in food samples. These results indicate that the AuNP/PCG nanocomposites have immense potential for the electrochemical detection of other biologically important compounds.