Preparation of Magnetic Imprinted Polymers Fe₃O₄@MIPs and Application in Sample Pretreatment of Plasticizer Detection of Edible Oil

Magnetic imprinted polymers were prepared by the modification of molecular imprinted polymers using magnetic materials by suspension polymerization. The modification conditions were 1∶6∶30 molar ratio of di-n-octylo-phthalate (template) to alpha methyl acrylic acid (monomer) to ethylene glycol dimethyl acrylate (cross-linking agent), 2.5% of initiator dosage (relative to the total weight of all monomers and cross linker), temperature 70 ℃, time 8 h. Magnetic imprinted polymers were characterized and their adsorption property was studied by UV-Vis spectrophotometry. Results showed that the adsorption amounts of magnetic imprinted polymers on dimethyl phthalate, dibutyl phthalate, benzyl butyl phthalate, di-n-pentyl phthalate and di-n-octylo-phthalate were 1.34, 1.45, 1.12, 1.50 and 1.72 mg·g^-1, respectively. The adsorption amounts of magnetic non-imprinted polymers on these substances were 0.79, 0.60, 0.75, 0.68 and 0.73 mg·g^-1, respectively. These results showed that imprinted polymer had better selective adsorption capacity than non-imprinted polymer. Actual sample analysis results showed that the magnetic imprinted polymers was superior to commercial column in adsorption capacity of plasticizer in edible oil, and could be used for sample pretreatment of di-n-octyl phthalate plasticizer detection of edible oil.