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Piezomicrogravimetric chemosensor for determination of selected alkaloids with dedicated porphyrin polymer film as recognition unit
|Krzysztof R. Noworyta 1, Wlodzimierz Kutner 1,2, Channa A. Wijesinghe 3, Serge G. Srour 3, Francis D'Souza 3|
1. Polish Academy of Sciences, Institute of Physical Chemistry, Kasprzaka 52/56, Warszawa 01-224, Poland
Two novel zinc porphyrins substituted with three electropolymerizable N,N-diphenylamines and either one or two acetamide side “arms” were synthesized for selective recognition of nicotine, cotinine, and myosmine. Subsequently, thin films of the porphyrin polymers were deposited on quartz crystal resonators by electrochemical polymerization under potentiodynamic conditions in order to fabricate a piezomicrogravimetric chemosensor. Spectral and electrochemical properties of the films as well as their surface morphology were characterized. Spectral results in combination with quantum mechanical calculations at the DFT level allowed for characterization of the polymer structure. They indicated that the porphyrin macrocycles remain essentially intact during electropolymerization for both porphyrin monomers used, as required for successful polymer application as the recognition unit in the chemosensor. Polymerization of the monomer bearing two and one acetamide “arm” resulted in films differing in morphology, porosity, and cross-linking. Electrochemical polymerization of the monomer bearing two acetamide arms apparently resulted in the film with more open structure than that of the film prepared by electropolymerization of the monomer with only one acetamide arm. The alkaloid interactions with the porphyrin polymer films were studied by using piezomicrogravimetry under flow-injection analysis conditions. All studied alkaloids bound reversibly to the porphyrin units of the polymers. For both porphyrins, nicotine binding was favored over binding of other alkaloids. Finally, analytical parameters of the devised piezomicrogravimetric chemosensor for alkaloid determination were evaluated.
Presentation: Short communication at SMCBS'2011 International Workshop, by Krzysztof R. Noworyta
See On-line Journal of SMCBS'2011 International Workshop
Submitted: 2011-10-25 02:00 Revised: 2011-10-26 14:56