Deep eutectic solvent-based molecularly imprinted polymer for the selective adsorption of emtricitabine in contaminated water

In this study, an eco-friendly deep eutectic solvent-based molecularly imprinted polymer (DES-MIP) was synthesized for the selective adsorption of emtricitabine in aqueous solutions. The molecularly imprinted polymer was synthesized via a bulk polymerization reaction using emtricitabine, deep eutectic solvent, ethylene glycol dimethacrylate, 1,1'-azobis-(cyclo-hexanecarbonitrile), ethanol–water (9:1 v/v) as a template, functional monomer, crosslinker, initiator and porogenic solvent, respectively. High-performance liquid chromatography equipped with a diode array detector was used to quantify emtricitabine after adsorption. The adsorption of emtricitabine obeyed the pseudo-second-order kinetic model, which is associated with the chemisorption process. This was observed through the regression coefficient (R²), which exceeded 0.99 for DES-MIP. Langmuir isotherm fitted the experimental data best with an excellent R² value of 0.99 for DES-MIP, thus indicating monolayer adsorption occurring on homogeneous binding sites. The maximum adsorption capacity was 4.649 mg g⁻¹ for DES-MIP. Furthermore, DES-MIP had high selectivity for emtricitabine with an extraction efficiency of 80% and a distribution coefficient of 1.59 mg g⁻¹ in the presence of competing compounds. This was attributed to the presence of selective binding sites on the surface of the imprinted polymer. Therefore, the present study showed that the synthesized DES-based MIP has great potential for use in the selective adsorption of emtricitabine from water systems.