Amperometric xanthine biosensors using glassy carbon electrodes modified with electrografted porous silica nanomaterials loaded with xanthine oxidase
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Glassy carbon electrodes were modified with silica materials such as silica nanoparticles, mesoporous silica nanoparticles and mesoporous silica thin films with the aim to introduce scaffolds suitable for the immobilization of enzymes. Xanthine oxidase was selected as a model enzyme, and xanthine as the target analyte. A comparison of the modified electrodes showed the biosensor prepared with mesoporous silica nanoparticles to perform best. By using the respective biosensor, xanthine can be amperometrically determined (via measurement of enzymatically formed hydrogen peroxide) at a working voltage of 0.7 V (vs. Ag/AgCl) with a 0.28 μM detection limit. The biosensor was evaluated in terms of potential interferences, reproducibility and stability, and applied to the determination of fish freshness via sensing of xanthine.
KeywordsMesoporous silica Silica nanospheres Electrografting Field–emission scanning electron microscopy Transmission electron microscopy Hexacyanoferrate Brunauer-Emmett-Teller
Authors wish to acknowledge the financial support to this work from the Tunisian Ministry of Higher Education and Scientific Research (MHESR) and the University of Tunis El–Manar for the mobility grant (Bourse d’Alternance) awarded to MS. RV acknowledge to Ramón & Cajal contract from the Spanish Ministry of Science and Innovation. Financial support from the Spanish Ministerio de Ciencia e Innovación CTQ2011–24355, CTQ2012–34238 and Comunidad de Madrid S2013/MIT–3029, Program NANOAVANSENS are gratefully acknowledged.
Compliance with ethical standards
The author(s) declare that they have no competing interests.
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