Electrochemical Characterization of Sulfide Tagging via Its Reaction with Benzoquinone Derivatives

The voltammetric response of a range of structurally diverse substituted benzoquinones species (p-benzoquinone, 2,3-dimethoxy- 5-methyl-p-benzoquinone, 2,6-dimethoxy-p-benzoquinone, and 3,5-ditert-butyl-o-benzoquinone) to increasing additions of sulfide has been examined using square wave voltammetry. In all cases the response shows that the quinone undergoes a reaction with sulfide to form a new redox active species. It is shown that by judicious choice of the pH of the solution analytical signals can be obtained for each species; the corresponding analytical parameters are detailed and the results critically appraised.