Determination of U(VI) and U(IV) concentrations in aqueous samples containing strong luminescence quenchers using TRLFS

Novel luminescence (LM) spectroscopy-based uranium (U) analysis methods are developed for aqueous samples containing strong LM quenchers. Reducing agents often found in biological samples, such as thiols, ascorbate and Fe(II) ions, are identified as the major strong quencher species. A strategy to selectively oxidize the reducing moieties of the quencher species using monopersulfate (the selected oxidant) is employed to rapidly reduce the LM quenching effects. Without requiring conventional sample pre-processing (ashing) procedures this method improves the limit of detection of U(VI) (∼nM levels) and enables rapid and simultaneous determination of U(VI) and U(IV) dissolved in biological samples containing strong quenchers. (author)