Electrochemical determination of adenine and adenosine: adsorption of adenine and adenosine at the pyrolytic graphite electrode.
Adenine and adenosine are polarographically reducible from aqueous solution at pH 4.7 at the DME at the same E(1 2 ) and are also voltammetrically oxidizable at the PGE, but at different potentials, adenosine at higher potentials. Competitive adsorption of both compounds at the PGE results in a decrease in the scanning voltammetric oxidation peak of adenine in the presence of adenosine, reaching a constant value when the concentration of the latter is above 6 mM. In mixtures, the sum of the two is obtained by polarography at the DME. Solid adenosine is then added to the solution and the adenine is determined by voltamrnetry at the PGE.
Dryhurst
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Department of Chemistry, University of Oklahoma, Norman, Oklahoma 73069, U.S.A.