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Solid-phase extraction of S-(-)-amlodipine from plasma with a uniformly sized molecularly imprinted polymer



To specifically extract S-(-)-amlodipine from plasma, uniformly sized molecularly imprinted polymers (MIPs) for S-(-)-amlodipine were prepared in an aqueous system by multistep swelling and polymerization with methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a crosslinker, and toluene as a porogen. Scanning electron microscopy was used to identify the structural features of the obtained polymers. 1H-NMR and high-performance liquid chromatographic analysis were performed to explore the possible recognition mechanism. The results reveal that spherical polymer beads with uniform size and good monodispersity were obtained, and the MIPs showed specific recognition ability for the template molecule. The ionic hydrophobic and hydrogen-bonding interactions were inferred to play an important role in the recognition mechanism. The results indicate that the MIPs could be used as a solid-phase extraction sorbent for the concentration and purification of S-(-)-amlodipine from plasma with a high efficiency. The linear range was 0.25–8.00 μg/mL with a correlation coefficient of 0.9948. The average recovery was 98.3% with relative standard deviation (RSD) less than 9.1%. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012