ELECTTROCHEMICAL SENSOR FOR THE SIMULTANEOUS VOLTAMMETRIC DETERMINATION OF ADENOSINE AND ADENINE

Abstract

Electrochemical method based on voltammetry using bare and single walled carbon nanotubes (SWNT) modified edge plane pyrolytic graphite electrode (EPPGE) is proposed for the simultaneous determination of adenosine and adenine in phosphate buffer medium of pH 7.2. The oxidation peak current of both the analytes increased significantly along with the negative shift of peak potentials using SWNT/EPPGE as compared to bare EPPGE. The modified electrode exhibited enhanced electrocatalytic properties towards oxidation of adenosine and adenine with a peak potential of-- 1190 mV and — 856 mV, respectively. The oxidation of both the compounds occurred in a pH dependent process, and the electrode reaction followed diffusion controlled pathway. The concentrations versus peak current plots were linear for both the analytes and the detection limit (36 / slope) observed for adenine and adenosine were 1.1 and 2.9 μM, respectively. The developed protocol is implemented for the simultaneous determination of adenosine and adenine in human urine samples of normal subjects.