Chemical speciation at the liquid-liquid interface: Development of a time-resolved-spectroscopy induced by the evanescent wave of a laser beam

Liquid-liquid extraction is essential to the spent nuclear fuel reprocessing industry, and future more efficient plants will require the development of increasingly selective chemical processes. Interactions between the actinides and organic ligands must be better understood for this purpose, particularly near liquid-liquid interfaces. We therefore undertook to develop a measuring instrument combining sensitivity and spatial localization for spectroscopic analysis of this particular zone. The standard nuclearization requirements concerning such instruments led us to develop a farfield optical system with the desired sensitivity, but its spatial localization potential was too adversely impacted by interface fluid movements. In the light of the experimental findings we have reexamined the measurement and nuclearization options.