Ultratrace Analysis of Actinides Via Coprecipitation/Laser-Induced Fluorescence Spectroscopy

摘要

Actinides were selectively preconcentrated by coprecipitating each out of solution with a fluoride matrix and calcining each sample at 800 exp 0 C. The fluorescence spectrum of each sample was recorded by illuminating the sample with laser light and detecting fluorescence with either a fluorescence/Raman spectrometer, an infrared spectrometer or in certain cases a filter fluorimeter. Three previously unobserved actinide spectra were recorded. Narrow lines at 546.9 nm, 564.6 nm, and 569.6 nm were found for CaF sub 2 :PuO sub 2++ at 10K. CaF sub 2 :Am exp +3 displayed two broadband fluorescent peaks at 625 nm and 746 nm at room temperature and CaF sub 2 :Pu exp +3 possessed a fluorescent peak at 1.22 microns at 10K. Energy transfer was observed in the form of Tb fluorescence quenching in TbF sub 3 :Pu exp +3 when Pu was present in quantities of 10 ppM or more and in the form of Tb fluorescence enhancement in TbF sub 3 :Am exp +3 when 1 ppM or more of Am was present. Careful sample preparation and the use of temporal as well as a spectral discrimination system extended the detection limit of U from 1 ml samples to the subfemtogram level. The fluorescence detection limits for Pu and Am were extended to 0.48 and 0.032 pg/ml. 39 figures, 9 tables. (ERA citation 08:018325)