Voltammetric determination of 6-mercaptopurine using a multiwall carbon nanotubes paste electrode in the presence of isoprenaline as a mediator

In this study, we describe the application of multiwall carbon nanotubes paste electrode (MWCNTPE) in the presence of isoprenaline (ISPT) as the suitable mediator for voltammetric determination of 6-mercaptopurine (6-MP) in aqueous buffer solution (pH 4.0). The results indicate that the electrode is efficient in terms of its electrocatalytic activity for the oxidation of 6-MP in the presence of ISPT as a mediator. Using chronoamperometry, the catalytic reaction rate constant was calculated at 1.68 x 10(-3) mu M-1 s(-1). The catalytic peak current was linearly dependent on 6-mercaptopurine concentration in the range of 0.5-900 mu M 6-MP. The detection limit (3 sigma) obtained by linear sweep voltammetry (LSV) was 0.1 mu M. Finally, the proposed method was also examined as a selective, simple and precise electrochemical sensor for the determination of 6-MP in real samples such as urine and tablet. (C) 2012 Elsevier B.V. All rights reserved.