Laser trapping and electrochemistry of a single oil droplet in water: Electron transfer across the oil-droplet | electrode interface

Abstract

The electrochemistry of ferrocene (FeCp) in a single micrometer-sized nitrobenzene droplet dispersed in water was studied by laser trapping and microelectrochemical techniques. Mass transfer of FeCp, ferrocenium ion, and tetra- n-butylammonium ion between the droplet and water phases accompanied by oxidation of FeCp proceeded across the droplet | water interface. The peak potential of a cyclic voltammogram of FeCp was highly dependent on the potential sweep rate. The potential shift was analyzed by thin-layer electrolysis and the results are discussed in terms of the irreversible electron transfer of FeCp across the droplet | electrode interface and in terms of mass transfer of ion species across the droplet | water interface.