Analytical and Bioanalytical Chemistry

, Volume 405, Issue 11, pp 3813–3822

Design of a new hypoxanthine biosensor: xanthine oxidase modified carbon film and multi-walled carbon nanotube/carbon film electrodes

  • A. Carolina Torres
  • M. Emilia Ghica
  • Christopher M. A. Brett
Original Paper

DOI: 10.1007/s00216-012-6631-1

Cite this article as:
Torres, A.C., Ghica, M.E. & Brett, C.M.A. Anal Bioanal Chem (2013) 405: 3813. doi:10.1007/s00216-012-6631-1

Abstract

A new and simple-to-prepare hypoxanthine biosensor has been developed using xanthine oxidase (XOD) immobilised on carbon electrode surfaces. XOD was immobilised by glutaraldehyde cross-linking on carbon film (CF) electrodes and on carbon nanotube (CNT) modified CF (CNT/CF). A comparison of the performance of the two configurations was carried out by the current response using amperometry at fixed potential; the best characteristics being exhibited by XOD/CNT/CF modified electrodes. The effects of electrolyte pH and applied potential were evaluated, and a proposal is made for the enzyme mechanism of action involving competition between regeneration of flavin adenine dinucleotide and reduction of hydrogen peroxide. Under optimised conditions, the determination of hypoxanthine was carried out at −0.2 V vs. a saturated calomel electrode (SCE) with a detection limit of 0.75 μM on electrodes with CNT and at −0.3 V vs. SCE with a detection limit of 0.77 μM on electrodes without CNT. The applicability of the biosensor was verified by performing an interference study, reproducibility and stability were investigated, and hypoxanthine was successfully determined in sardine and shrimp samples.

Keywords

Hypoxanthine biosensorXanthine oxidaseCarbon film electrodesCarbon nanotubesFlavin adenine dinucleotide

Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • A. Carolina Torres
    • 1
  • M. Emilia Ghica
    • 1
  • Christopher M. A. Brett
    • 1
  1. 1.Departamento de Química, Faculdade de Ciências e TecnologiaUniversidade de CoimbraCoimbraPortugal