Table 1: Formation constants of the binary complexes of DPA at 25 °C and I = 0.1 M ionic strength.


System l p qa log βb Sc

DPA 0 1 1 7.65(0.04) 4.99E−6
0 1 2 10.21(0.06)
Co-DPA 1 1 0 4.55(0.02) 4.69E−7
Cu-DPA 1 1 0 7.65(0.01) 1.18E−7
Mn-DPA 1 1 0 4.01(0.04) 5.31E−7
1 1 1 8.21(0.02)
Ni-DPA 1 1 0 6.88(0.02) 9.49E−7
Zn-DPA 1 1 0 5.87(0.03) 5.68E−7

al, p, and q are the stoichiometric coefficients corresponding to MII, HL, and H+, respectively;
bStandard deviation is given in parentheses;
cSum of square of residuals.