Voltammetric determination of adenosine and guanosine using fullerene-C60-modified glassy carbon electrode

A fullerene-C-60-modified glassy carbon electrode (GCE) is used for the simultaneous determination of adenosine and guanosine by differential pulse voltarnmetry. Compared to a bare glassy carbon electrode, the modified electrode exhibits an apparent shift of the oxidation potentials in the cathodic direction and a marked enhancement in the voltammetric peak current response for both the biornolecules. Linear calibration curves are obtained over the concentration range 0.5 mu M-1.0 mM in 0.1 M phosphate buffer solution at pH 7.2 with a detection limit of 3.02 x 10(-7) M and 1.45 x 10(-7) M for individual determination of adenosine and guanosine, respectively. The interference studies showed that the fullerene-C-60-modified glassy carbon electrode exhibited excellent selectivity in the presence of hypoxanthine, xanthine, uric acid and ascorbic acid. The proposed procedure was successfully applied to detect adenosine and guanosine in human blood plasma and urine, without any preliminary pre-treatment. (c) 2006 Elsevier B.V. All rights reserved.