Electrocatalytic determination of hydrazine concentrations with polyelectrolyte supported AuCo nanoparticles on carbon electrodes

Gold–cobalt alloy nanoparticles (AuCo NPs) deposited on a screen-printed carbon electrode (SPCE) surface modified with a combination of polystyrene sulfonate (PSS) and poly-3,4-ethylenedioxythiophene (PEDOT) is demonstrated for monitoring the direct oxidation of hydrazine. The surface morphology and properties of PSS:PEDOT supported AuCo NPs modified carbon electrodes were characterized using field-emission scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopic analysis. The current change with respect to the electrocatalytic oxidation of hydrazine on AuCo NPs/PSS:PEDOT/SPCE was used for the quantitative analysis in conjunction with cyclic, linear sweep, and differential pulse voltammetries alongside chronoamperometry (CA). The voltammetric response for the oxidation of hydrazine using AuCo NPs/PSS:PEDOT/SPCE was also compared with those of bare SPCE and PSS:PEDOT/SPCE. Under optimum conditions using CA, the modified electrode offered a linear range from 0.5 to 1000 μM, a sensitivity of 1.64 µA µM⁻¹ and a limit of detection of 0.17 µM. The stability, reproducibility, sensitivity, and selectivity were also investigated. Finally, the AuCo NPs/PSS:PEDOT/SPCE platform was employed to determine native hydrazine concentrations in local river water samples.