Photometric complex-formation titration of submicromole amounts of uranium.
With DTPA present in excess, small amounts of uranium (100-200 mug) can be reduced quantitatively to the quadrivalent state in a Jones reductor (5% amalgamated Zn powder, 50 mesh). The excess of DTPA is back-titrated photometrically with thorium, with Semi-Xylenol Orange as the indicator. The accuracy is +/- 0.2 mu g at the 200-mu g level. Metals forming complexes with DTPA at pH 2 interfere.
Kragten
J
J
Laboratory for Analytical Chemistry, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands.
Ozinga
W
W