Abstract: A commercially available reagent zinc(II)-protoporphyrin (ZnPP) is used as a novel fluorescent functional monomer to synthesize molecularly imprinted polymers (MIPs) for the selective recognition of histamine. ZnPP having a Lewis acid binding site Zn, binds with the imidazolyl group of histamine through coordination. Association constant (K-ass) and the number of accessible sites (N) between the MIP and the template are found to be dependent upon the template concentration. By using Scatchard's plot, the K-ass and N are determined as 4500 l/mol and 180 mumol/g when the concentration of histamine is 0.1-1 mmol/l, but the two values are obtained, respectively, as 270 l/mol and 1100 mumol/g when the concentration is 4-10 mmol/l. The binding ability was also evaluated more accurately with a multi-binding model. Highly binding affinity is found for the ZnPP-based polymer than that only using methacrylic acid (MAA) as a functional monomer. Fluorescence intensity of the MIP decreased with histamine concentration but saturation behavior is observed when the histamine concentration is above 1 mmol/l, indicating that histamine no longer coordinated with ZnPP in the MIP and led to the low association constant at this condition. (C) 2002 Elsevier Science B.V. All rights reserved

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