title: Covalent imprinted polymer for selective and rapid enrichment of ractopamine by a noncovalent approach.
abstract: A novel molecularly imprinted polymer (MIP) for the separation and concentration of ractopamine (RAC) was prepared by a covalent imprinting approach and the template was removed successfully by hydrolysis, so that four carboxylic acid groups were left in the cavities and could specifically rebind RAC through noncovalent interaction: hydrogen bonding. The conditions for synthesis of the MIP were optimized during the polymerization process, and a molar ratio of template-functional monomer complexes to cross-linker of 1:3 was confirmed. The adsorption capacity of the MIP was 4.1-fold that of the nonimprinted polymer, and the adsorption reaction reached equilibrium after 25 min at 50 mg L(-1) concentration. The results of the competitive adsorption test showed that the MIPs had specific recognition ability for the analyte RAC. In addition, the important factors affecting the efficiency of the method which was developed using the MIPs as a solid-phase sorbent for separation and determination of RAC combined with high-performance liquid chromatography with fluorescence detection were optimized. Under the optimum experimental conditions, the linear range of the calibration curve in the method was 0.05-5 μg L(-1) (R(2)=0.98) and the limit of detection (signal-to-noise ratio of 3) was 0.01 μg L(-1). The proposed method was applied to determination of RAC in spiked feedstuffs and urine samples, with recoveries ranging from 74.17 to 114.46% and relative standard deviation (n=3) below 4.55 in all cases.
authors.affiliation: Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science & Technology, Tianjin 300457, China.
authors.forename: Yi-Wei
authors.initials: YW
authors.lastname: Tang
authors.forename: Guo-Zhen
authors.initials: GZ
authors.lastname: Fang
authors.forename: Shuo
authors.initials: S
authors.lastname: Wang
authors.forename: Jia-Le
authors.initials: JL
authors.lastname: Li
mesh_terms: D000318:Adrenergic beta-Agonists / Q000302:isolation & purification / Q000378:metabolism; D000327:Adsorption; D002851:Chromatography, High Pressure Liquid; D005453:Fluorescence; D054802:Molecular Imprinting; D010627:Phenethylamines / Q000302:isolation & purification* / Q000378:metabolism*; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism*; D052616:Solid Phase Extraction
chemical_list: D000318:Adrenergic beta-Agonists; D010627:Phenethylamines; D011108:Polymers; C060897:ractopamine