Synthesis of Well-Dispersed Silver Nanoparticles on Polypyrrole/Reduced Graphene Oxide Nanocomposite for Simultaneous Detection of Toxic Hydrazine and Nitrite in Water Sources

The AgNPs@PPy/rGO composites were synthesized by interfacial polymerization method using organic solvent dispersion of pyrrole as a reducing agent for graphene oxide. Aqueous solution of silver nitrate was used as a precursor for Ag nanoparticles and oxidizing agent to initiate polymerization reaction at the interface. The nanocomposite film electrode was employed for the electrochemical oxidation of inorganic pollutants namely hydrazine and nitrite and their oxidation potential was observed at +0.53 and +0.76 V (vs. Ag/AgCl), respectively in phosphate buffer. The kinetic parameters such as diffusion coefficient (1.67 × 10 −5 and 3.9 × 10 −5 cm 2 /s) and electron transfer rate constant (3.03 × 10 6 and 8.36 × 10 5 M −1 s −1 ) of hydrazine and nitrite were measured by chronoamperometric method. Differential pulse voltametry was employed to determine individual as well as simultaneous detection of both analytes with well-resolved peak potential window (∼470 mV). The linear dynamics range from 0.6 μM to 6.6 μM and the detection limit of 19 and 21 nM for hydrazine and nitrite respectively were observed. In addition, the proposed sensor shows an enhanced stability and found to be incentive to select pollutants and biomolecules.