Abstract
The valence state of technetium-99 in its complexes with bleomycin, 1-hydroxy-ethylidene-1,1-diphosphonate and human serum albumin was determined by titration of 99TcO4− with Sn(II) in the presence of these complexing agents. Both direct titration, and addition of an excess of Sn(II) and back-titration with iodine was employed.