Detection of uric acid based on multi-walled carbon nanotubes polymerized with a layer of molecularly imprinted PMAA

A molecularly imprinted poly-methacrylic acid (PMAA), polymerizing on the surface of multi-walled carbon nanotubes (MWCNTs), was synthesized. The MWCNTs were modified by a layer of carboxylic acid and reacted with 1-ethyl-3-(3-dimethylamino-propyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) to activate the carboxylic acid, which was prepared for the purpose of bonding allyl amine and getting an unsaturated side chain (-CH=CH2). The molecularly imprinted polymers (MIPs) based on PMAA were polymerized on the surface of MWCNTs-CH=CH2 with the addition of uric acid (UA). The non-imprinted polymers (NIPS) were polymerized without adding UA. The adsorbed amount of UA approached the equilibrium value upon 10 min adsorption. The adsorption isotherms suggest that the MIP particles adsorb higher amount of UA than that of NIP particles and possess a good imprinting efficiency of about 4.41. The adsorption isotherms were correlated successfully by the Freundlich model and the micro-pore adsorption behavior was considered. Amperometric detection also declared similar aspect than the adsorption results and shows high selective property due to the electro-active ascorbic acid (AA). (C) 2009 Elsevier B.V. All rights reserved.