Kinetic Analysis of the Solvent Extraction of Cadmium(II) Complexes Using a Cadmium-deposited Recessed Microelectrode and Confocal Fluorescence Microscope.

Using a Cd-deposited microelectrode, an electrochemically generated Cd(II) ion in a micro-water phase was reacted with 5-octyloxymethyl-8-quinolinol (HC8Q) in 1,6-dichlorohexane. The fluorescence intensity of Cd(C8Q)2 near the water/oil interface (IF) was analyzed under a confocal fluorescence microscope. The rate of decrease of IF was independent of the HC8Q concentration and pH, but was influenced by the phase-boundary potential between the water and oil phases, suggesting that Cd(II) extraction is governed by Cd(C8Q)+ desorption at the interface.