Nanosized magnetite and nafion modified gold wire electrode for electrochemical monitoring of nitrite in water

Nitrite ions have been a concern for both environmental and health issues. It is crucial to monitor the nitrite level to battle these problems. In this work, a Fe₃O₄/Nafion-modified gold electrode has been utilized to detect the nitrite ion using electrochemical methods. Fe₃O₄ nanoparticles are synthesized via electrolysis. Fe₃O₄ nanoparticles are successfully synthesized and produce a relatively small size of 51.4 nm. Attenuated Total Reflectance-Fourier transform infrared (ATR-FITR) analysis confirmed the interaction of Fe₃O₄ nanoparticles with Nafion. The Cyclic Voltammetry (CV) analysis shows that the proposed electrode has the highest oxidation peak for nitrite. The Electrochemical Impedance Spectroscopy (EIS) analysis suggests that the proposed electrode exhibits the lowest resistance. Scan rate analysis confirms that the nitrite oxidation reaction is diffusion-controlled. Limit of Detection (LOD) analysis using both CV, Differential Pulse Voltammetry (DPV), and amperometry analysis produces a LOD of 0.1074, 0.0504, and 0.0003 mg/L, respectively. Interference analysis, performed by amperometry with various compounds, demonstrates that the proposed electrode is selective for nitrite ions. Stability analysis confirms the proposed electrode produces a stable signal for prolonged use. Reproducibility analysis also showed that the electrode makes the same signal in different batches. Real sample analysis of a pond water sample using amperometry and compared to spectrophotometry shows no significant difference between the two methods, making the proposed method a viable alternative for sensitive, selective, and real-time analysis of nitrite ions in water samples.