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Molecularly imprinted solid‐phase extraction for the selective HPLC determination of ractopamine in pig urine
Author(s) -
Zhang Qingjie,
Su Yijuan,
He Qianqian,
Shen Xianguang,
He Limin,
Zhang Nan,
Zeng Zhenling
Publication year - 2011
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201100655
Subject(s) - ractopamine , molecularly imprinted polymer , chromatography , chemistry , solid phase extraction , molecular imprinting , high performance liquid chromatography , analyte , extraction (chemistry) , methanol , sample preparation , detection limit , selectivity , organic chemistry , catalysis
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.