Carbonized polymer dots-based molecular imprinting: An adsorbent with enhanced selectivity for highly efficient recognition and removal of ceftiofur sodium from complex samples.

Highly selective removal of residual cephalosporin antibiotics from complex systems is crucial for human health and ecological environment protection. Herein, a newly molecularly imprinted polymer adsorbent (CPDs-NH@MIP) with enhanced selectivity for ceftiofur sodium (CTFS) was developed by using the special carbonized polymer dots (CPDs-NH) as functional monomer. The CPDs-NH has a nano-spherical structure and functionalized groups (CC, -NH) via the incomplete carbonization polymerization of citric acid, acrylamide and ethylenediamine, which can accurately interact with CTFS by overcoming steric hindrance, resulting in more precisely imprinted sites and reducing non-imprinted regions in MIP. The presented CPDs-NH@MIP exhibited excellent adsorption capacity for CTFS (68.62 mg g), achieving equilibrium within 10 min, and highly selectivity in mixed solution containing five coexisting substances, with an imprinted factor (5.61). Compared with commercial adsorbents and MIPs prepared with traditional chain functional monomers, the CPDs-NH@MIP showed significant advantage in selective recognition and separation of target. Analysis of microstructure and mechanism proved that usage of the spherical functional monomer generated precise imprinting sites and dense structure in CPDs-NH@MIP, which effectively enhanced the selectivity in complex system combined with hydrogen bonding interaction. The idea of designing and using spherical functional monomer will promote the practicality of molecularly imprinted polymer adsorbents.