Electrochemiluminescence from direct electro-oxidations of organic analyte rutin and its analytical application

This paper reported an electrochemiluminescence (ECL) from direct electrochemical oxidation of organic analyte rutin itself that was different from both annihilation and coreactant ECL in mechanism. The ECL production mechanism could be described as follows: rutin was electrochemically oxidized via one-electron transfer to o-semiquinone radical. Then the radical was further electrochemically oxidized via one-electron transfer to the excited state rutin o-quinone that subsequently emitted light. Based on the ECL of rutin, a flow injection ECL method for the determination of rutin was proposed. In the proposed flow injection system, an ECL signal was generated in rutin–NaOH–cetyl trimethyl ammonium chloride solution by applying direct current of 12 mA to the platinum anode in an ECL flow-through cell with two-electrode system. The ECL intensity of rutin was proportional to its concentration over the range of 6.0 × 10−7–1.0 × 10−5 mol l−1, and the limit of detection (s/n = 3) is 2 × 10−7 mol l−1. The proposed method had been evaluated by the analysis of rutin in pharmaceutical preparations.