Time-resolved laser-induced fluorescence has been shownto be effective for on-line measurement of uranyl chelatesin supercritical carbon dioxide. Quenching and otherfactors affecting the method's accuracy were identified andquantified to allow for accurate measurements undervariable supercritical fluid conditions. The method wasapplied to the kinetic analysis of uranium extraction fromacidic solutions with tributyl phosphate modified supercritical carbon dioxide.