| Popis: |
Summary The preconcentration of uranium from natural waters at μg l -1 levels with an iron dibenzyldithiocarbamate carrier complex followed by vacuum filtration, collection of the precipitate as a thin-film and wavelength-dispersive x-ray fluorescence spectrometry is described. Ultraviolet irradiation was utilized to reduce the effect of humic substances so that filtration of larger volumes of sample became possible and lower amounts of uranium could be determined. Coprecipitation was most effective at pH 4 with a relative percent recovery of 94% or better determined from acid digestion of the precipitates and furnace atomic absorption spectrometry. A detection limit of 0.4 μg l -1 was achieved for 500-ml water samples with a counting time of 300 s. Of the ions tested (Mg 2+ , Ca 2+ , Na + , K + , SO 2- 4 , Cl - ) none were observed to interfere at concentrations of 100 ppm or less. The applicability of the method to environmental water samples was assessed by spiking actual water samples and determining the amount of uranium present. The results showed the method to be reliable and applicable to environmental water samples. |
