title: Molecularly imprinted solid-phase extraction for the selective HPLC determination of ractopamine in pig urine.
abstract: A method was developed for the determination of ractopamine in pig urine using molecularly imprinted solid-phase extraction (MISPE) as the sample clean-up technique combined with high-performance liquid chromatography. The molecularly imprinted polymer (MIP) was synthesized in acetonitrile-triethylamine system using ractopamine (RAC) as the template and acrylamide as the monomer. The binding capacity of the polymer toward RAC was found to be about 2.57 mg of ractopamine/g of polymer. The optimal procedures for MISPE consisted of conditioning with 3 mL methanol, equilibrating with 3 mL of water, loading volume of <10 mL of aqueous sample (pH 7), washing with 3 mL water and 3 mL methanol, and eluting with 5 mL of 5% ammonia in methanol. In the four spiked samples with the levels of 0.01, 0.1, 1.0 and 5.0 μg/mL, the mean recoveries of analyte on the MIP were higher than 90% with relative standard deviation <10%, and significant differences between imprinted and non-imprinted materials were observed. The MIP selectivity was evaluated by checking 11 drugs with similar and different molecular structures to that of RAC. The characteristics of three-dimensional cavities and hydrogen bond interaction were regarded as the main factors that dominated the retention of RAC on the MISPE cartridge.
authors: Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong, PC, P. R. China.
authors: Qingjie
authors: Q
authors: Zhang
authors: Yijuan
authors: Y
authors: Su
authors: Qianqian
authors: Q
authors: He
authors: Xianguang
authors: X
authors: Shen
authors: Limin
authors: L
authors: He
authors: Nan
authors: N
authors: Zhang
authors: Zhenling
authors: Z
authors: Zeng
mesh_terms: D000318:Adrenergic beta-Agonists / Q000302:isolation & purification* / Q000652:urine*; D000327:Adsorption; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D054802:Molecular Imprinting; D010627:Phenethylamines / Q000302:isolation & purification* / Q000652:urine*; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000295:instrumentation / Q000379:methods*; D013552:Swine
chemical_list: D000318:Adrenergic beta-Agonists; D010627:Phenethylamines; D011108:Polymers; C060897:ractopamine