Ultratrace determination of adenine in the presence of copper by adsorptive stripping voltammetry

An electrochemical stripping procedure for ultra-trace measurements of aden ine is described based on the adsorption of the adenine-copper complex on a static mercury drop electrode. Cyclic voltammetry was used to characterize the interfacial and redox behavior. Optimum experimental conditions were f ound when using a 0.005 M NaOH solution containing 0.4 ppm of copper, an ac cumulation potential of -0.30 V, a scan rate of 100 mV s(-1) and a linear s can mode. There is a linear response to adenine concentration in the range of 0.1-1.0 ppb and the detection limit for 6 min accumulation time was of 4 .0 ppt (3.0 x 10(-11) M). Proper conditions for measuring the adenine in pr esence of guanine, thymine and cytosine were also investigated. The method was applied for the determination of adenine in a sample of single-stranded calf thymus DNA. (C) 2001 Elsevier Science B.V. All rights reserved.