Ferrocene sulfonates as electrocatalysts for sulfide detection

The electrochemical characterization of both the mono- and di-substituted forms of ferrocene sulfonate are given. The results show both species produce voltammograms consistent with quasi-irreversible diffusion controlled redox reactions. The FcSO3− species was found to be easier to oxidize than its Fc(SO3)22− counterpart, due to the electron withdrawing affect of the sulfonate group on the Fe centre.In the presence of sulfide, the voltammetric response of FcSO3− is shown to be consistent with the occurrence of an electrocatalytic EC′ reaction. This analytical response was utilized as a means of determining sulfide and was found to be linear over the concentration 0.02–1 mM with a limit of detection of 14 μM.