Fluorescence spectroscopy on protactinium(IV) in aqueous solution

This work focuses on time-resolved laser fluorescence spectroscopy (TRLFS) of Pa(IV) in aqueous solution. Excitation at 308 nm causes a fluorescence emission with a peak maximum at about 460 nm. Thereby, the position of the band's maximum depends on the concentration, the type of the acid, and the pH value. Increasing complexation of the Pa(IV) ion leads to an increasing hypsochromic shift of the emission band up to 46 nm. In contrast to the band position the half-width (61.6 +/- 1.4 nm) and the lifetime (16 +/- 2 ns) of the fluorescence emission do not change significantly with changes in the chemical environment of the Pa(IV). The results of this work show that speciation of Pa(IV) can be performed even in aqueous solution by using TRLFS.