The electrochemical analog of the methylene blue reaction: A novel amperometric approach to the detection of hydrogen sulfide

The electrochemical oxidation of N,N-dimethylphenylenediamine at glassy carbon electrodes in aqueous solution in the pH range 3-6 is shown to lead to currents which are considerably amplified in the presence of dissolved hydrogen sulfide. The mechanism of the electrode process is investigated and the reaction is shown to provide an attractive basis for the amperometric sensing of sulfide with an accessible range of ca. 3 to 150 muM (0.1 to 4.8 ppm).