Determination of Hypoxanthine in the Presence of Copper by Adsorptive Stripping Voltammetry

Abstract

A stripping method for the determination of hypoxanthine in the presence of copper at the submicromolar concentration levels is described. The method is based on controlled adsorptive accumulation of hypoxanthine-copper at the thin-film mercury electrode followed by a fast linear scan voltammetric measurement of the surface species. Optimum experimental conditions were found to be the use of 1.0 × 10 −3 mol·L −1 NaOH solution as electrolyte supporting, an accumulation potential of −0.50 V and a linear scan rate of 200 mV·s −1 . The response of hypoxanthine-copper is linear over the concentration ranges of 10 -60 ppb. For an accumulation time of 30 minutes, the detection limit was found to be 250 ppt (1.8 × 10 −9 mol·L −1 ). Adequate conditions for measuring the hypoxanthine in the presence of metal ions, xanthine, uric acid and other nitrogenated bases were also investigated. The utility of the method is demonstrated by the presence of hypoxanthine associated in ATP or ssDNA.