IJUP08 - Universidade do Porto

Hydrogen Peroxide Reversible Luminescence Sensors
Célia Rocha and Joaquim C.G. Esteves da Silva
Department of Chemistry, CIQ-UP, Faculty of Sciences, University of Porto, Portugal.
The determination of reactive oxygen species (ROS) is a matter of great importance in the
study of numerous physiological and pathological processes. The production of ROS,
which includes hydrogen peroxide, is mediated by multiple oxidative stress mechanisms
responsible for changes in the cells and tissues. Beside this role in these pathological
processes they are also involved in numerous physiological process of regulation in the
organism.
With the objective to develop luminescent sensors for in vitro and in vivo measurement of
hydrogen peroxide two reversible detection methods are being optimized [1,2]. A direct
assay of hydrogen peroxide at neutral pH using the Eu(III)-tetracycline complex. This
complex in aqueous solution binds to hydrogen peroxide to form a fluorescent complex
with increased fluorescence at 613 nm when is excited at 400 nm.
The second method is an H2O2 sensor based on the room-temperature phosphorescence of
the nanocomposite TiO2/SiO2. The TiO2/SiO2 composite was prepared by the sol-gel route
and produces phosphorescence at about 600 nm when excited at 400nm (Fig. 1) – in the
presence of hydrogen peroxide the phosphorescence emission is quenched.
Int.
10000
5000
0
596
400 600 800
Wavelength (nm)
Fig. 1 – Phosphorescence emission spectra (Ex. 400 nm) of the TiO2/SiO2 composite.
This communication will present and discussed the results of these two reversible detection
methods for hydrogen peroxide.
Acknowledgements: Financial support from Fundação para a Ciência e Tecnologia (Lisboa)
(FSE-FEDER) (Project PTDC/QUI/71001/2006) is acknowledged.
References:
[1] Durkop, A., Wolfbeis, O.S., (2005), Nonenzimatic Direct Assay of Hydrogen Peroxide at
Neutral pH using the Eu3Tc Fluorescent Probe, Journal of Fluorescence, 15 (5), 755-761.
[2] Shu, X., Chen, Y., Yuan, H., Gao, S. and Xiao, D. (2007), H2O2 Sensor Based on the Room-
Temperature Phosphorescence of Nano TiO2/SiO2 Composite, Anal. Chem, 79 (10), 3695-3702.
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