Adenine Determination in the Presence of Copper in Diluted Alkaline Electrolyte by Adsorptive Stripping Voltammetry at the Mercury Film Electrode

Abstract

AbstractHighly sensitive, simple and inexpensive techniques of adenine determination are particularly interesting in relation to the present development of ATP and DNA sensors. A nanomolar concentration of adenine can be determined in the presence of copper. For an accumulation time of 30 minutes, the detection limit found was 0.22 ppb (1.63×10−9 M). The method is based on controlled adsorptive accumulation of adenine‐copper at thin‐film mercury electrode followed by linear scan voltammetric measurement of the surface species. By applying a condition time of 60 s at −0.9 V, the same thin‐film can be used over several measurements. Optimum experimental conditions were found to be the use of a 5.0×10−3 M NaOH solution, an accumulation potential over the −0.20 to −0.40 V range, and a scan rate of 100 mV s−1. The response of adenine‐copper is linear over the concentration range 20–100 ppb. The more convenient ways to measuring adenine in the presence of metals and other nitrogenated bases were also investigated. The adenosine triphosphate (ATP) or deoxyribonucleic acid (DNA) are first treated with acid (e.g., 0.1 M perchloric acid), and the acid‐released adenine (without separation from others products of the degradation) is directly determined by adsorptive stripping voltammetry.