Selective Voltammetric and Flow-Injection Determination of Guanosine and Adenosine at a Glassy Carbon Electrode Modified with a Ruthenium Hexachlororuthenate Film

An inorganic film of ruthenium hexachlororuthenate (RuRuCl₆), deposited on the surface of a glassy carbon electrode, exhibits electrocatalytic activity in the oxidation of purine nucleosides, such as guanosine and adenosine. Appropriate operating conditions are found for fabricating a polymer film on the surface of glassy carbon and for recording the maximum electrocatalytic current for the modified electrode. A method for the selective voltammetric determination of guanosine and adenosine in their simultaneous presence at an electrode modified by a RuRuCl₆ film is developed. A procedure is proposed for the amperometric detection of purine nucleosides with this modified electrode under the conditions of flow-injection analysis. The linear dependence of the analytical signal on the concentration of guanosine and adenosine is observed up to 5 × 10^–6 M in the stationary mode and up to 5 × 10^–7 M in the flow system. The proposed method for the selective determination of guanosine and adenosine was tested in the analysis of human urine.