Study of thorium hydrolysis species by electrospray-ionization mass spectrometry Original Research Article

Electrospray-mass spectrometry (ES-MS) has been used for the first time to study the hydrolysis of thorium. Hence, important discrepancies exist in the literature concerning the appearance of the first hydroxo complex. By studying thorium species as a function of pH, it was possible to observe the appearance of the first thorium hydroxo complexes at pH 1 as well as the other hydroxo complexes at higher pH. By using MS/MS experiments, all thorium complexes corresponding to the different hydroxo thorium species, Th(OH)3+, Th(OH)22+, Th(OH)3+ were attributed. Speciation of Th-hydrolyzed complexes obtained by ES-MS is compared to that obtained in the literature.