Phosphate Ion-Selective\nElectrode Based on Electrochemically\nModified Iron

The significance\nof the detection of phosphate ions is immense\nin the realms of chemistry, biology, medicine, environment, and industry.\nThe detection of phosphate ions is currently mainly reliant on blue\nmolybdenum colorimetry, which is accurate but requires sample pretreatment,\nintricate operation, and a high price tag. Consequently, it is essential\nto create a sensor with superior efficiency, precision, straightforward\nfunctioning, and instantaneous online detection. This study has designed\nand created an electrochemical modification based on an iron metal\nelectrode for this purpose. Cyclic voltammetry was used to initially\nascertain the potential (−0.57 V) necessary for constant potential\nelectrolysis. Employing a constant potential electrolysis method,\nthe iron oxide and its phosphate were modified onto the surface of\nthe iron electrode to enable reaction with phosphate ions. Scanning\nelectron microscopy and energy dispersive X-ray spectroscopy were\nused to characterize and analyze the morphology and elemental composition\nof Fe-PME, elucidating how it responds to phosphate ionation. The\ntwo-electrode system was then utilized for the evaluation of the phosphate\nion response of Fe-PME at pH 4. Fe-PME’s response to phosphate\nions is demonstrated by the results, ranging from 10<sup>–5</sup> to 0.1 M and with a slope of −52.8 mV dec<sup>–1</sup>. Fe-PME exhibited satisfactory results when compared to the conventional\nblue colorimetry of molybdenum.