The stability constants of different complex species of some metal ion viz. Hg(II), Be(II) and Ni(II) with cysteine were determined electrophoretically at an ionic strength of 0.1 M percholoric acid and 35-degrees-C. Beside binary complexes ternary complexes involving NTA and amino acid (Cysteine) have also been studied. For studying mixed ligand complexes the background electrolyte is made 1 x 10(-2)M with respect to NTA and its pH brought to 8.5. This pH is purposely chosen because amino acid and NTA form very stable complexes much a head of this pH. The stability constant of complexes M-NTA- Cysteine have been found to 5.06, 4.93 and 4.88 (log K values) for Hg(II), Be(II) and Ni(II) complexes respectively.


R K P SINGH ,K L YADAVA ,B B TIWARI ,R CHANDER ,