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 submi- cromolar concentration levels is described. The method is based on controlled adsorptive accu- mulation 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 poten- tial 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 detec- tion limit was found to be 250 ppt (1.8 × 10−9 mol·L−1). Adequate conditions for measuring the hy- poxanthine 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 asso- ciated in ATP or ssDNA.