A Highly Selective Electrochemical Biosensor for Di-2-Ethylhexyl Phthalate Detection by Using Single-Use Conjugated Polymer Coated Electrode

This work reported a novel electrochemical biosensor based on indium tin oxide (ITO) modified with epoxy-substituted polythiophene (Poly(Thi-Epoxy)) polymer for sensitive detection of di-2-ethylhexyl phthalate (DEHP), the most extensively used phthalate. DEHP-specific aptamer was utilized as a biorecognition molecule and provided selective analysis of DEHP. Poly(Thi-Epoxy) polymer was coated on the disposable working electrode to form a stable surface with epoxy groups for immobilization of aptamer. Electrochemical techniques were used to follow the electrochemical behaviour of the biosensor. The applicability of the biosensor toward DEHP sensing was investigated by electrochemical impedance spectroscopy (EIS) measurements, and the concentration of DEHP was measured through the increase in EIS signal change. Using this strategy, DEHP could be detected in the linear range of 0.5 to 300 pg/mL with a relatively low detection limit (LOD) of 0.144 pg/mL. Along with its exceptional sensitivity and selectivity, this biosensor demonstrated acceptable repeatability and reproducibility, long storage stability, and amazing reusability. The biosensor was successfully used to analyze DEHP in migrating water samples, indicating a promising practical application. In comparison to the gas chromatography (GC) method, the aptasensor that was created was ultimately effective in measuring DEHP. As a result, this strategy offered a promising method for developing a biosensor for the detection of phthalates.