Preparation of molecularly imprinted polymers for sensing of 2,4-dichlorophenoxyacetic acid residues in environmental water and mixed juice

In this paper, we reported a rapid and simple approach to synthesize molecularly imprinted polymers (MIPs) materials for sensing of 2,4-dichlorophenoxyacetic acid (2,4-D) residues in environmental water and mixed juice. Initially, MIPs materials were prepared via visible light-initiated reversible addition-fragmentation chain transfer (RAFT) emulsion polymerization at ambient temperature using 2,4-D and its analogs as template molecules, in which 4-vinyl pyridine (4-VP), ethylene glycol dimethacrylate (EGDMA), (2,4,6-trimethylbenzoyl) diphenylphosphine oxide (TPO), 2-(((dodecylthio)carbonothioyl)thio)-2-methylpropanoic acid (DDMAT) were functional monomer, cross-linker, visible light initiator and RAFT agent, respectively. Then, the morphologies of the MIPs materials were characterized by FT-IR, SEM and DLS. The results showed that the MIPs materials were well-distributed spherical particles with sizes ranging from 1 to 2 μm. Furthermore, a four-channel MIPs sensor array included four polymer microspheres with a fluorescent dye displacement procedure was developed to distinguish the templates and their chemical analogs at the ppm concentration level. With the support of principal component analysis and hierarchical cluster analysis, the four-channel MIPs sensor array proves to be a simple and effective method to recognize and distinguish the templates and nontemplates in aqueous solution with 100% accuracy. Finally, the four-channel MIPs sensor array was also found to have satisfactory accuracy in monitoring 2,4-D contaminated environmental water and mixed juice.