Sensitive determination of ATP using a carbon paste electrode modified with a carboxyl functionalized ionic liquid

We report on a new electrode for the determination of adenosine-5'-triphosphate (ATP). It is based on modified carbon paste electrode that contains an ionic liquid (IL) as the binder. The electrode shows strong electrocatalytic oxidative activity towards ATP at pH 4.5 in giving a well-defined single oxidation peak. The oxidation reaction is adsorption-controlled and due to the presence of the highly conductive IL. The electron transfer rate constant was calculated to be 2.04x10(-3) s(-1), and the surface coverage is 1.11x10(-10) mol cm(-2). Under the selected conditions, the oxidation peak current changes linearly with the concentration of ATP in the range from 5.0 to 1000 mu mol L-1 and a detection limit of 1.67 mu mol L-1 (3 sigma) as determined by differential pulse voltammetry. The method displays good selectivity and was applied to the determination of ATP injection samples with satisfactory results.