Molecularly imprinted polydopamine-based sensor for accurate paracetamol monitoring in environmental samples

Abstract In this study, an electrochemical sensor based on a molecularly imprinted polymer (MIP) was successfully designed for acetaminophen (paracetamol) detection. We utilized density functional theory (DFT) to choose the most appropriate monomer among four monomers that can interact with paracetamol to create specific recognition sites: pyrrole, o-phenylenediamine, p-phenylenediamine and dopamine. Calculations indicated that the most suitable monomer was dopamine. The MIP was consequently designed by electropolymerizing dopamine in the presence of paracetamol and extracting the templates from the vicinity of the polymeric matrix with ethanolic washing. The MIP-based electrochemical sensor exhibited a limit of detection of 0.55 10 −10 mg.mL −1 (0.72 pM) and a sensitivity equal to (0.83 ± 0.07) µA.cm −2 /mg.mL −1 . The dissociation constant K d , related to paracetamol analytes affinity with the imprints, was estimated from the fitting of the calibration curve with a combined power-Hill model. It was of the order of (1.22 ± 0.86)×10 −8 mg.mL −1 . The selectivity and the competitive tests were investigated with four molecules having chemical structures and molecular weights comparable to paracetamol: tyrosine, proline, 4-nitrophenol and pyridine-3-carboxylic acid. Electrochemical results highlight the ability of the designed sensor to detect paracetamol even in the presence of high concentrations of interfering molecules. Measures were also performed in seawater, wastewater, and hospital effluent. The findings highlight the potential of this analytical tool to screen paracetamol in complex and real aquatic environments.