EMF / mV
Adj. EMF / mV
440
420
420
E0 = 409.28mV
s = 62.01
jc = -6.77
400
380
360
340
340
360
380
400
Raw EMF / mV
400
380
360
0
5
10
15
20
25
30
V (HCl) / mL
Figure S1: Calibration plot for a Metrohm combination electrode in 1M NaCl titrated with
standardized 1M HCl at 25.0 ± 0.1°C, V0 = 20mL. The solid curve (—) represents the raw EMF
in mV and the dashed curve (– –) represents the adjusted EMF according to the equation:
Eadj(mV) = E - jc[H+] = E0 + slog[H+], where E0 is the standard electrode potential, s is the slope
factor, and jc is the junction correction factor. The insert plots Eadj against the raw E values. The
data were adjusted using the program VLpH and were exported to the Hyperquad program for
titrations of Th(IV) with DTPA.
100
Ce(III)DTPA
Ce(III)
% Ce
75
50
Ce(III)HDTPA
25
0
1
2
3
4
5
6
pH
Figure S2: A speciation diagram for a Ce(III) (2mM) and DTPA (4mM) system at 1M (K+) ionic strength
and 25°C. The dissociation constants of DTPA and stability constants for Ce(III)DTPA and
Ce(III)HDTPA are listed in Table 1.
40
An(IV)DTPA
slope = 44 3
35
logβ101
30
U
Th
25
20
Ln(III)DTPAb
slope = 27.9
15
Np
Pu
An(IV)EDTAa
slope = 35.1
Gd
La
Ln(III)EDTAb
slope = 19.6
10
0.7
0.8
0.9
1
1.1
1.2
R-1 (Å-1)
Figure S3: ♦ Stability constants for Th(IV), U(IV), Np(IV), and Pu(IV)DTPA complexes
reported in this work (I = 1M, 25°C); ♦ Stability constants for Th(IV), U(IV), Np(IV), and
Pu(IV)EDTA complexes reported in reference 38 (I = 0.5M, 25°C); ■ Stability constants for LaGd(III)DTPA (sans Pm(III)) reported in reference 22 (I = 0.5M, 25°C); ■ Stability constants for
La-Gd(III)EDTA (sans Pm(III)) reported in reference 22 (I = 0.5M, 25°C).