Au-on-Pd bimetallic nanoparticles applied to the voltammetric determination and monitoring of 4-nitroaniline in environmental samples

Abstract

Palladium@Gold bimetallic nanoparticles (Au-on-PdNP) were synthesized and characterized by X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). The nanomaterial was successfully applied in the modification of a glassy carbon electrode (GCE). By using the modified electrode and cyclic voltammetry (CV), a pronounced current response was obtained for the noxious compound 4-nitroaniline (4-NA), an environmental pollutant. Using differential pulse voltammetry (DPV), the anodic peak currents increased by increasing 4-NA concentrations in the range of 0.5–50 µmol L−1, with a limit of detection of 0.17 µmol L−1. The proposed method was successfully applied to the determination of 4-NA in river water samples, at different levels, with a recovery range of 90–106%. Selectivity was investigated, showing that, at a significance level of 95%, the matrix did not interfere with the analysis. Accuracy was evaluated using molecular absorption spectrometry. Consistent results were obtained with accuracy and precision showing that the novel method can be successfully used for environmental purposes as an alternative strategy. The electrode also presents long-term stability, showing that Nf/Au-on-Pd/GCE may be applied as an electrochemical sensing platform for the 4-NA detection in environmental analysis with a focus on management and in-loco monitoring.