Magnetite-Integrated Electrochemical Sensor for Efficient Detection of PET Microplastics in Water

Plastic pollution, particularly from microplastics, poses serious risks to ecosystems and human health. Polyethylene terephthalate (PET), a widely used polymer, commonly leaches into food and water sources, necessitating effective monitoring. This study presents a simple electrochemical sensor for trace detection of PET microplastics in water. The sensor was developed by modifying a screen-printed gold electrode (SPAuE) with magnetite (Fe₃O₄) nanoparticles valorized from mill scale. Electrochemical analysis revealed a fully irreversible, diffusion-controlled oxidation response. Under optimized conditions, the SPAuE/Fe₃O₄ sensor successfully detected PET in the concentration range of 6.25 to 500 mg/L, with a detection limit of 3.6 mg/L. The improved performance is attributed to the high conductivity and surface area of Fe₃O₄ nanoparticles. The sensor exhibited excellent sensitivity, selectivity, reproducibility, stability, and practical applicability in both synthetic and real water samples, supporting its potential as a simple, portable, and cost-effective tool for monitoring PET pollution in aquatic environments.