Electrochemical sensing of 5-aminosalicylic acid via DES-based molecularly imprinted polymers/rGO: experimental and theoretical insights.

5-Aminosalicylic acid (5-ASA), a common anti-inflammatory, is an emerging contaminant due to its widespread presence in aquatic environments and ecological risks. Developing sensing platforms for its trace detection is essential for environmental monitoring. This study developed a highly selective molecularly imprinted polymer (MIP) combined with reduced graphene oxide (rGO) for electrochemical detection of 5-ASA. A Deep Eutectic Solvent (DES), chosen for its eco-friendliness and excellent solvating ability, served as the functional medium to improve the imprinting process. The synthesis was suggested by molecular dynamics (MD) simulations and Quantum Theory of Atoms in Molecules (QTAIM) theory, which identified an optimal molar ratio of 3 : 1 : 3 for choline chloride : caffeic acid : ethylene glycol. The MIP/rGO sensor exhibited excellent analytical capabilities, including a wide linear range (0.3-700 μM) and a low detection limit (0.15 μM). It also demonstrated high selectivity against interferents and was effectively used on water samples, confirming its reliability as a sensor for pharmaceutical residues in water systems.