Gold nanoparticles modified polypyrrole/reduced graphene oxide nanocomposites (AuNPs@PPy/rGO) were synthesized by an interfacial polymerization method. The prepared nanocomposites were isolated and characterized using various analytical techniques to find the morphology, crystalline nature, and functional groups.

The AuNPs@PPy/rGO modified GCE was further evaluated using EIS and CV techniques. Moreover, the nanocomposites improved electrocatalytic activity by acquiring lower overpotentials, high peak current densities, and large surface areas. Chronoamperometric studies were used to measure the diffusion coefficient (1.23 × 10−5 cm2/s and 2.17 × 10−5 cm2/s) and catalytic reaction rate constant (4.05 x 106 M−1s−1 and 9.60 x 105 M−1s−1) of hydrazine and nitrite. DPV technique was employed to determine the individual as well as the simultaneous determination of both analytes, and the detection limits were found to be 9.9 nM and 16.5 nM for hydrazine and nitrite at AuNPs@PPy/rGO/GCE.

Fabricated electrodes reveal better outstanding features like long-term stability, repeatability, and strong anti-interference ability. Finally, the proposed electrode was used to determine the hydrazine and nitrite concentration in water samples (drinking, tap, and lake) with better recovery ranges.