Development of molecularly imprinted polymer-based electrochemical sensors for the detection of UV filters in aquatic ecosystems

The presence of organic UV filters (OUVAs) has been detected worldwide in aquatic ecosystems. These pollutants, originating from various anthropogenic sources, can persist and transform within wastewater treatment plants (WWTPs), posing a potential environmental hazard. In this framework, this research presents electrochemical sensors based on molecularly imprinted polymers (MIPs) for the selective detection of Benzophenone-3 (BP-3) and Octocrylene (OC), two of the OUVA most spread in the aquatic environment, to overcome the analytical challenges related to the quantification of this class of contaminants in wastewater samples. Key parameters, including the selection of the electropolymerization conditions, the template washing, polymer surface blocking, and analyte re-binding conditions, were optimized to maximize the selectivity and sensitivity. Electrochemical detection was performed using electrochemical impedance spectroscopy (EIS) supported by an electrochemical probe. In addition, cross-reactivity tests were carried out in the presence of possible interferents, selected based on their size, chemical structure, and occurrence in wastewater samples. The sensors demonstrated significant selectivity and sensitivity for the target analytes, with detection limits of 30 nM for BP-3 and 1 nM for OC, while tests on complex wastewater samples showed recovery rates of 77 % and 101 % for BP-3 and OC, respectively. The study yielded interesting results that could lead to a specific, cost-effective approach to enable widespread monitoring and support early detection of these increasingly relevant contaminants in wastewater samples.