Simultaneous Detection of 4-Nitroquinoline-1-oxide and Nitroimidazole Drug Using a Perovskite-BaZrO₃@Nb₄N₅-Nanocomposite-Modified Disposable Carbon Electrode

Pharmaceutical ingredients in water have become a serious threat to living bodies and lead to assorted ecological predicaments. In this study, we have established an electrochemical probe for the simultaneous detection of synthetic pharmaceutical ingredients, including 4-nitroquinoline-N-Oxide (NQN) and ornidazole (ODZ), in both human and environmental samples. This study establishes the detection of NQN and ODZ using a screen-printed carbon electrode (SPCE) modified by highly conducting Nb₄N₅ incorporated with BaZrO₃ perovskite. The electrochemical characteristics of the modified SPCEs were explored by different techniques including electrochemical impedance spectroscopy, differential pulse voltammetry, and cyclic voltammetry. The structural and morphological parameters of the synthesized BaZrO₃@Nb₄N₅ probe were confirmed by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and Brunauer-Emmett-Teller techniques. The modified probe shows excellent sensing characteristics, such as a very low detection limit up to 16.9 nM for NQN and 8.6 nM for ODZ with a wide linear range varying from 0.02 to 84.5 μM and 0.02 to 99.12 μM, respectively. The analytical performance of the modified SPCEs was successfully verified by incorporating the probe for detecting NQN and ODZ in real samples together with wastewater and human urine. Finally, the applicability of our proposed method was validated through a standard HPLC technique.