Study On Fluorescent Sensor Of Molecularly Imprinted Polymers For The Pesticide Metolcarb

The situation of food security is increasingly severe, one of the issues which affects our health and ecological balance is pesticide residue. Exploring a fast, easy and sensitive method for the detection of pesticide residue is imperative. Novel fluorescent molecularly imprinted polymers has been synthesized and applied to the determination of trace metolcarb in real samples.In this article, a molecularly functionalized polymer with fluorescence which can selective and recognize metolcarb was prepared by bulk polymerization method using metolcarb as the template,2-acrylamidopyridine-acrylamide as the fluorescent functional monomer, methacrylic acid as the co-monomer,ethylene glycol dimethacrylate as the cross-linker and2,2’-azobisisobutyronitrile as the initiator. The experiment results showed that the property of fluorescent functional monomer was stable and high purity; different polymerization conditions and reactant ratio had important influence on the adsorption of the imprinted polymer. The fluorescent imprined polymer could present the best sorption and selective ability under the condition with adding the solvent of0.50mL acetonitrile and0.50mL toluene, the mol ratio of template molecule,fluorescent functional monomer, co-monomer and cross-linker of1:1:2:20, controlling the temperature at40℃, reacting48h, removing of template molecule48h.The resulted imprinted polymer was evaluated by static absorption,kinetic absorption, selective experiments and characterized by FT-IR, SEM, fluorescence spectrophotometry. It indicated that the imprinted polymer had well ability.93.25%of metolcarb could be adsorbed by the prepared material after adsorbing for3h, and adsorption equilibrium was obtained within4h at metolcarb concentration of40.00mg/L. The distribution coefficient for metolcarb on the imprinted polymer is32.45mg/g, higher than on the non-imprinted polymer of14.81mg/g. The data also proved that the fluorescent imprined polymer had high selective ability and fast mass transfer rate.The material was further used as the fluorescent sensor. After the adsorption of metolcarb, fluorescent functional monomer conducted the signal and displayed on fluorescence spectrum. With increasingly adding the concentration of metolcarb,fiuorescence intensity gradually deceased. The samples of three juice, determined to be free of metolcarb, were spiked with four levels of metolcarb (50μg/L,100μg/L,150μg/Land200μg/L) before detection using the method discussed above. The results demonstrated were in accordance with the quenching tendency under different concentration proposed. It is proved that the new method studied was easy, sensitive and feasible.