Simultaneous Determination of Uranium and HNO₃Concentrations in Solution by Laser-Induced Fluorescence Spectroscopy

A simultaneous determination method of U and HNO₃, concentrations by fluorescence spectroscopy was proposed. In the method, the former was determined from UO₂²⁺fluorescence intensity which is proportional to UO₂²⁺ion concentration and the latter from UO₂²⁺fluorescence spectrum profile which depends on the N0₃^-ion configuration around the UO₂²⁺ion. The UO₂²⁺ fluorescence spectra were measured by a laser-induced fluorescence spectrometer which was capable of remote measurement by utilizing fiber optics. The fluorescence spectrum profiles were evaluated by normalized integrated fluorescence intensities in the wavelength region of 510~650 nm. The U and HN0₃ concentrations were determined in the ranges of 1~200 mg/dm³ with an accuracy of 0.5 mg/dm³, and 0.75~6.0 mol/dm³ with an accuracy of 0.1 mol/dm³, respectively.