Preparation And Application Of The Molecularly Imprinted Polymer For Ractopamine

Ractopamine may be used in livestock production as a new type of additives to promote growth.But when the accumulated dose exceeds a certain value in our body,it is easy to have some toxic reactions.As the complexity of animal-derived food matrix and the trace of veterinary drug residue,it is necessary to establish a high selective and sensitivity analytical technique with efficient sample pretreatment.In this article,a molecularly imprinted functionalized polymer for selective separation of ractopamine was prepared by combining a surface molecular imprinting technique with a sol-gel method process using ractopamine as template,3-aminopropyltriethoxysilane as functional monomer,tetraethoxysilicane as crosslinker and silica gel as support material.The experiment results showed that polymerization conditions had important influence on the adsorption and selective recognition ability of the imprinted polymer.When the imprined polymer was polymerized with the solvent of methanol,the mol ratio of template molecule,functional monomer and cross-linker of 1:4:4,and the reaction temperature of 40℃,it had higher sorption capacity and selective ability.The results of adsorption experiments indicated that the imprinted polymer had high selective ability and and fast mass transfer rate.The distribution coefficient for ractopamine on the imprinted polymer is 16.81 mL g^-1,higher than on the non-imprinted polymer of 6.79 mL g^-1 and the saturated adsorption capacity(Q_max) of imprinted polymer was 1.990 mg g^-1.The prepared polymer was applied for the determination of trace ractopamine through on-line solid-phase coupled with high performance liquid chromatography(SPE-HPLC). The ractopamine in the pork was determined at three levels(0.5μg kg^-1,1.0μg kg^-1 and 2.0μg kg^-1) with the recoveries ranging from 55.86%to 67.28%.The experiment offered a new type of adsorption material for detection ractopamine and the method which is simple and accurate can meet the requirements of trace residues in veterinary drugs.