Probing of silver oxide nanoblades for 4-hydroxybenzoic acid quantification: a tool for food and water safety assessment

From various emerging harmful contaminants, 4-hydroxybenzoic acid (HBA) has gained considerable recent attention due to its penetration into certain consumer products. In our research, for the first time, we report the synthesis and utilization of novel-shaped silver oxide nanoblades (Ag2O NBs) towards direct electrochemical sensing of HBA. The synthesis of Ag2O NBs was accomplished using a chemical method to produce nanoblades with a thickness of 15-20 nm, high homogeneity (band gap 2 eV), crystallinity, and a cubic unit cell. The electrocatalytic competence of the synthesized Ag2O NBs was established through their admittance behavior and capability towards oxidation of HBA. The fabricated Ag2O NBs/Nafion/Au electrode was evaluated electrochemically for its conduction behavior and elec-trocatalytic activity towards oxidation of 4-hydroxybenzoic acid (HBA) into phenoxonium ion. A cyclic voltammetry (CV) technique was standardized and optimized for the determination of HBA content in authentic samples, and the results were found to be in close agreement with that of spiked samples. The selectivity of the fabricated electrode and standardized technique was also evaluated in the presence of potential interfering species. This fabricated sensor demonstrated a detection limit of 4.58 ppm (linear range: 5-50 ppm) and sensitivity of 83.87 mA cm-2 ppm-1. Additionally, the practicability of the fabricated sensor was realized through analysis of various types of field samples.(c) 2022 Elsevier Ltd. All rights reserved.