Sustainable graphene-based molecularly imprinted polymer for selective solid-phase extraction of triclosan: From tap...

Triclosan (TCS), a widely used antimicrobial agent, is recurrently detected in environmental and biological matrices. Its environmental persistence and potential endocrine-disrupting effects raise significant toxicological concerns. Sensitive and selective analytical strategies are therefore essential for trace-level monitoring in complex samples.

A straightforward graphene-based molecularly imprinted polymer (Gr@MIP) was developed to produce highly selective sorbents for TCS. Graphene (Gr), obtained by electrochemical exfoliation, was functionalized with 9-vinylcarbazole. This functionalization ensured efficient anchoring of the imprinted network. Gr@MIP was synthesized via a user-friendly oil-in-water emulsion photopolymerization. 2-vinylpyridine (2VP) was employed as the functional monomer. Comprehensive characterization (fluorescence, infrared spectroscopy, thermogravimetric analysis, microscopy, and granulometry) demonstrated efficient grafting and a robust, controlled morphology. Gr@MIP-2VP demonstrated outstanding molecularly imprinted solid-phase extraction (MISPE) performance. It achieved excellent selectivity with imprinting factors up to 2.5 in serum. Cross-reactivity studies revealed that the two-phenyl-ring scaffold structure governs molecular recognition. The synergistic coupling of MISPE with HPLC-UV and UHPLC-MS/MS enabled accurate trace-level quantification (0.05 μg/L in tap water and 1 μg/L in fetal bovine serum). It achieved recoveries near 100% and preconcentration factors up to 500. Furthermore, the sorbent maintained its recognition capacity over more than 40 extraction cycles, outperforming conventional commercial phases.

This work introduces an original, sustainable Gr-assisted imprinting approach. It combines simple surface functionalization with eco-friendly MISPE protocols. By achieving high selectivity and enrichment capability in diverse matrices while offering exceptional reusability, this strategy represents a cost-effective and promising alternative to conventional SPE phases. Furthermore, the conductive Gr core is promising for the future development of integrated electrochemical sensing platforms for endocrine-disrupting contaminants.