Selective recognition of paracetamol using optimized deep eutectic solvent-molecularly imprinted polymer

Abstract

An optimized deep eutectic solvent-molecularly imprinted polymer (DES-MIP) was synthesized via a straightforward bulk polymerization using choline chloride (ChCl) and methacrylic acid (MAA) (1:2) as the functional monomer, paracetamol as the template, and ethylene glycol dimethacrylate (EGDMA) as the crosslinker. Response surface methodology (RSM) with central composite design (CCD) optimized the main constituent ratio (template, functional monomer, and crosslinker), yielding a synthesis ratio of 1:4:20 mmol and a highest binding capacity of 8.899 mg/g. The model’s robustness was supported by a high F-value (54.05) and low p-value (< 0.001). At the same time, analysis of variance (ANOVA) indicated that the template and functional monomer significantly influenced binding capacity compared to the crosslinker. Characterization of DES-MIP included analyses of functional groups, molecular structure morphology, thermogravimetric properties and porosity analysis. Selectivity tests demonstrated a superior binding capacity (8.89 mg/g) and imprinting factor (3.85) for paracetamol relative to salicylic acid ( 4.42 mg/g, 3.05) and aspirin (4.08 mg/g, 3.85). The absorption kinetics and isotherm were best described by pseudo-second-order kinetics and the Langmuir model, respectively, at an optimum pH of 7 using 5 mg of DES-MIP as adsorbent. DES-MIP showed good stability, retaining 19.5% efficiency after 20 reusability cycles. Application to real samples of herbal drinks, medicine, and health Supplements achieved recoveries of 96.46%, 88.80%, and 86.20%, with relative standard deviations (RSD) of 1.25%, 2.42%, and 2.56%. These findings highlight DES-MIP as a promising alternative for paracetamol removal or extraction with high selectivity, good reusability, and reliable analytical performance.