title: Determination of technetium and its speciation by surface-enhanced Raman spectroscopy.
abstract: Technetium-99 (Tc) is an important radionuclide of concern, and there is a great need for its detection and speciation analysis in the environment. For the first time, we report that surface-enhanced Raman spectroscopy (SERS) is capable of detecting an inorganic radioactive anion, pertechnetate (TcO4-), at approximately 10(-7) M concentration levels. The technique also allows the detection of various species of Tc such as oxidized Tc(VII) and reduced and possibly complexed Tc(IV) species by use of gold nanoparticles as a SERS substrate. The primary Raman scattering band of Tc(VII) occurs at about 904 cm-1, whereas reduced Tc(IV) and its humic and ethylenediaminetetraacetic acid (EDTA) complexes show scattering bands at about 866 and 870 cm-1, respectively. Results also indicate that Tc(IV)-humic complexes are unstable and reoxidize to TcO4- upon exposure to oxygen. This study demonstrates that SERS could potentially offer a new tool and opportunity in studying Tc and its speciation and interactions in the environment at low concentrations.
authors.affiliation: Environmental Sciences Division, Oak Ridge National Laboratory, and Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37831, USA. gub1@ornl.gov
authors.forename: Baohua
authors.initials: B
authors.lastname: Gu
authors.forename: Chuanmin
authors.initials: C
authors.lastname: Ruan