The formation constants of dimethylthallium(III)-glutathione complexes in aqueous solution

The complexes formed in the dimethylthallium(III) (Me2Tl+), glutathionate ( EGC(3-)) and hydrogen ion system in aqueous solution at 37 degrees C and I = 150 mmol dm(-3) (NaCl) have been characterised by means of glass-electrod e potentiometry. Glutathione protonation constants were found to be 9.123 /- 0.007, 17.42 +/- 0.01, 20.78 +/- 0.02, and 22.93 +/- 0.02. Formation con stants for the complexes [ (Me2Tl) EGCH](-) and [(Me2Tl)EGC] (2-) were foun d to be 11.19 +/- 0.03 and 2.39 +/- 0.02, respectively. Particular attentio n has been paid to the evaluation of the effect of possible systematic erro rs on the constant values determined. Reliable standard deviation estimatio ns have been made by applying a Monte Carlo calculation technique. (C) 1999 Elsevier Science Inc. All rights reserved.