Gold nanoparticle-based sensing platform of hydrazine, sulfite, and nitrite for food safety and environmental monitoring

Background: A facile and sensitive electrochemical sensor platform has been explored based on gold nanoparticles (Au NPs) dispersed in amine-functionalized three-dimensional (3D) silicate sol–gel network for ((aminopropyl)triethoxysilane (APS)-Au NPs) for multi-analytes such as hydrazine, sulfite, and nitrite. Methods: Au NPs dispersed silicate network was prepared via a single-step chemical reduction strategy. The Au NPsbased sensor platform was fabricated through drop-cast on a glassy carbon (GC) electrode. Results: The fabricated APS-Au NPs-based sensor was characterized by ultraviolet–visible (UV–Vis) spectroscopy, cyclic voltammetry (CV), and scanning electrochemical microscopy (SEM). The resultant sensor was employed for the electrocatalytic and sensor applications towards hydrazine, sulfite, and nitrite in 0.1 M phosphate buffer (PB) (pH 7.2). The APS-Au NPs sensor exhibited an excellent catalytic activity in the absence of any other electron transfer mediators/enzyme immobilized at the electrode surface. The electrocatalytic oxidation of hydrazine, sulfite, and nitrite occurs at ~40, ~170, and ~550 mV, respectively, which is lesser positive potential of ~810, ~735, and ~393 mV for the oxidation of hydrazine, sulfite, and nitrite, respectively, than that of the bare GC electrode. Moreover, the present sensor showed low detection limits of 10 nM, 100 nM, and 1 μM for hydrazine, sulfite, and nitrite respectively. Conclusions: APS-Au NPs sensor highlights the successful design for sensitive detection of multi-target analytes for food safety and environmental monitoring applications.