Films based on TiO2 nanoparticles (NPs) have been successfully used as sensing elements in chemical sensors. TiO2 colloidal suspensions can be obtained by spontaneous hydrolysis in acidic solutions of Ti(IV) compounds. The obtained TiO2 NPs can be employed to build up nanostructured films. With the purpose of preparing TiO2-based nanostructured, imprinted materials as sensing elements for piezoelectric sensors, we obtained TiO2 NP dispersions by hydrolyzing potassium titanyl oxalate in the presence of a target analyte (tyrosine). Since morphological properties of the synthesized NPs are known to influence the nanostructured film characteristics, an analytical strategy to characterize such colloidal systems can combine a size-based separation method with spectroscopic analysis to correlate the particle size distribution (PSD) with the particle-target interaction properties able to determine the sensing efficiency. In this work, we present the characterization of colloidal tyrosine-TiO2 NP systems by flow field-flow fractionation (FlFFF) with online, UV/Vis absorption detection and offline fluorescence analysis. FlFFF eliminates the possible contribution of free tyrosine to the absorption and fluorescence properties of the NPs. FlFFF also fractionates NPs on a size basis. Particle size distribution (PSD) profiles of the fractionated NPs are then obtained by conversion of the multi-wavelength UV/Vis fractograms. Size of the fractionated NPs is finally related to fluorescence properties of the collected NPs fractions. Good correlation between the fluorescence intensity, which is proportional to the tyrosine uptake, and the FlFFF-based, NP mass-size frequency distribution finally confirms the existence of tyrosine-TiO2 NP interaction. © 2006 Elsevier B.V. All rights reserved.
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|Titolo:||Characterization of titanium dioxide nanoparticles imprinted for tyrosine by flow field-flow fractionation and spectrofluorimetric analysis|
|Data di pubblicazione:||2007|
|Appare nelle tipologie:||1.1 Articolo in rivista|