Molecular imprinting-based fluorescent chemosensor for histamine using zinc (II)–protoporphyrin as a functional monomer

A Tong, H Dong, L Li - Analytica Chimica Acta, 2002 - Elsevier
A Tong, H Dong, L Li
Analytica Chimica Acta, 2002Elsevier
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 (Kass) 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 Kass and N are determined …
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 (Kass) 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 Kass and N are determined as 4500l/mol and 180μmol/g when the concentration of histamine is 0.1–1mmol/l, but the two values are obtained, respectively, as 270l/mol and 1100μmol/g when the concentration is 4–10mmol/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 1mmol/l, indicating that histamine no longer coordinated with ZnPP in the MIP and led to the low association constant at this condition.
Elsevier
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