Well-defined magnetic surface imprinted nanoparticles for selective enrichment of 2,4-dichlorophenoxyacetic acid in real samples

Superparamagnetic core-shell molecularly imprinted polymer nanoparticles (MIPs) were prepared via surface initiated reversible-addition fragmentation chain transfer (si-RAFT) polymerization for the selective recognition of 2,4-dichlorophenoxyacetic acid (2,4-D) in real samples. The construction of uniform core-shell structure with a 50 nm MIP layer was successfully accomplished, which favored mass transfer and resulted in fast recognition kinetics. The static equilibrium experiments revealed the satisfied adsorption capacity and imprinting efficiency of Fe3O4@MIP. Moreover, the Fe3O4@MIP exhibited high selectivity and affinity towards 2,4-D over structural analogues. The prepared Fe3O4@MIP nanoparticles were used for the selective enrichment of 2,4-D in tap water and Chinese cabbage samples. Combined with RP-HPLC, the recoveries of 2,4-D were calculated from 93.1% to 103.3% with RSD of 1.7-5.4% (n = 3) in Chinese cabbage samples. This work provides a versatile approach for fabricating well-constructed core-shell MIP nanoparticles for rapid enrichment and highly selective separation of target molecules in real samples.