Rapid redox sensing of p-nitrotoluene in real water samples using silver nanoparticles

Abstract

In the present work, a robust silver nanoparticle-based electrochemical sensor for the sensing of p-nitrotoluene (p-NT) has been described. The silver nanoparticles were synthesized using sonochemical technique and their purity, morphology and stability were established by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray, X-ray powder diffraction and thermogravimetric analysis; SEM and EDX analysis revealed an interesting structure of AgNPs containing p-NT, different from the usual AgNPs. The synthesized AgNPs were embedded over Au electrode for electrochemical-based efficient sensing of p-nitrotoluene (p-NT) in real water and laboratory sample. The mechanism of the 4-NT reduction reaction was examined using cyclic voltammetry (CV) while the electrochemical sensing of 4-NT was carried out using chronoamperometry; measurement of reduction peak current was observed with a regression coefficient of 0.987 which increased further upon enhancing the concentration of p-NT. The sensor also exhibited a linear response for the reduction of 4-nitrotoluene in the range of 0.01–0.10 µM with high sensitivity of 6.36 µA/µM cm2, and a very low limit of detection 0.092 µM. Overall, the results showed that the proposed AgNPs/Au electrode presents an efficient option for detecting the lowest concentration of p-NT wherein the sensor displays robust sensing platform with good reproducibility, stability, and selectivity toward the analytes in real as well as laboratory sample analysis.