Influence of pH on hanging mercury drop electrode cyclic voltammetry with aspartic acid in acetate buffers

Department of Chemistry, Anna University, Chennai-600 025, India

Manuscript received 20 September 2007, revised 25 January 2008, accepted 19 February 2008

As the supporting electrolyte (acetate buffer) itself interacts with mercury, the Hg-acetate current is always superimposed on the Hg-amino acid interaction current. Hence whether amino acid is present or not there will be the current of Hg-acetate leading to intercept on the current axis of the I_P vs [aspartic acid] plot. There arc three processes deduced from Hg-amino acid solution interaction. They are process A, B and C. Process A is due to mercuric mercury complex formation, Hg⁰ + (asp) ↔ Hg₂²⁺ (asp) and process 8 is due to mercurous mercury complex formation, Hg⁰ + (asp) ↔ Hg₂²⁺ (asp). Process C is the result of mercury-acetate interaction. The peak potentials are shifted to less positive values with increasing pH.