Table 8. Overall Stability Constants (logβ) for the Cu⁺ Complexes Formed by DO4S, DO3S, and DO2A2S at I = 0.15 mol/L and T = 25°C and Calculated pCu⁺ Values at Different pH Values^a.

			pCu+
ligand	equilibrium reaction	logβ	pH 4.0	pH 6.0	pH 7.4
DO4S	Cu+ + L ⇋ CuL+	19.8 ± 0.2	10.7	14.7	17.2
DO3S	Cu+ + L ⇋ CuL+	17.2 ± 0.2	7.9	11.9	14.5
DO2A2S	Cu+ + L2– ⇋ CuL–	16.7 ± 0.1	7.3	11.3	14.1

^apCu⁺ calculated at C_Cu⁺ = 10^–6 mol/L and C_L = 10^–5 mol/L