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-NH2@MIP) with enhanced selectivity for ceftiofur sodium (CTFS) was developed by using the special carbonized polymer dots (CPDs-NH2) as functional monomer. The CPDs-NH2 has a nano-spherical structure and functionalized groups (C=C, −NH2) 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-NH2@MIP exhibited excellent adsorption capacity for CTFS (68.62 mg g−1), 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-NH2@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-NH2@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. Ceftiofur sodium (CTFS) antibiotic residues in the environment and food pose potential threats to ecosystems and human health; thus, developing highly selective and eco-friendly sample pretreatment technologies holds significant importance for the efficient recognition of CTFS. Molecularly imprinted polymers (MIPs) present a promising approach in the development of selective adsorbents for CTFS. However, conventional MIPs employing chain functional monomers demonstrate restricted imprinting factors and susceptibility to interference, thereby limiting their practical applicability. This work employs carbonized polymer dots-derived novel spherical functional monomers to fabricate MIPs with enhanced selectivity, which would inspire more ideas to implement in high-selectivity adsorbent construction.