This manuscript describes a new protocol for determination of Pa/Th/U in marine sediments. It is based on microwave-assisted digestion and represents an important reduction of working time over conventional hot-plate digestion methods, and the use of HClO4 is avoided. Although Th and U are completely dissolved with a first microwave step, around 40% of 231Pa remains undis- solved, and a short hot-plate step with reverse aqua regia is required to achieve total digestion and spike equilibration. Next, the method involves a separation of these elements and a further purification of the Pa fraction using Dowex AG1-X8 resin. Separation with Bio-Rad and Sigma-Aldrich resins was compared; although both perform similarly for Th and U, Pa yields are higher with Bio-Rad. Finally, samples are measured using a Nu instruments multiple collector inductively coupled plasma mass spectrometer (MCICPMS). Overall chemical yields range around 50% for Pa, 60% for Th, and 70% for U. © 2009 American Chemical Society.
|Publication status||Published - 1 Mar 2009|
Negre, C., Thomas, A. L., Mas, J. L., Garcia-Orellana, J., Henderson, G. M., Masqué, P., & Zahn, R. (2009). Separation and measurement of Pa, Th, and U isotopes in Marine sediments by microwave-assisted digestion and multiple collector inductively coupled plasma mass spectrometry. Analytical Chemistry, 81, 1914-1919. https://doi.org/10.1021/ac802341y