Some aspects of actinide speciation by laser-induced spectroscopy

Abstract During the past decade many studies on speciation of actinides in natural and artificial environments have been carried out. High demands on the sensitivity in speciation of actinides lead to the development of advanced detection methods. This is connected with intensive use of laser systems as excitation sources. The laser can provide any wavelength from the near UV to the near infrared (NIR) wavelength range. The development of tunable solid-state lasers overcame some disadvantages of dye laser systems. The application of low temperatures for samples measured with fluorescence spectroscopic methods brought effort in the detection of carbonate species. The availability of modern femtosecond laser systems in combination with intensified charge coupled device (ICCD) cameras provided the possibility to exploit the fluorescence properties of aromatic organic compounds for the study of their interaction with actinides, especially non-fluorescent metal ions. The fluorescence of some tetravalent actinides as Pa(IV) and U(IV) in aquatic systems have been described for the first time. The speciation of actinides in arsenate and several carbonate systems was investigated. The interaction with ligands from life sciences as adenosine triphosphate (ATP) and sugar phosphates became more and more important. Studies of the speciation of actinides in plants and microorganism also cannot be neglected. In the solid-state the speciation of uranium(VI) in several natural and synthetic minerals has been studied as well as the behaviour of depleted uranium in the environment. The interaction of actinides with rock materials and minerals as well as their uptake is also of common interest in actinide chemistry. Especially the sorption and inclusion of Cm into several minerals lead to an improvement in knowledge of minor components in solids. It is not possible to give a complete overview on the literature about the laser-induced spectroscopy of actinides. The restricted length of this contribution allows only a relatively small and personally influenced selection.