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Constant Current Stripping Chronopotentiometry for the Study of Adsorbing Inert and Electrochemically Nonreversible Metal Complexes at Low Concentrations: Application to Cd and Zn Metallothioneins

  1. Núria Serrano1,
  2. Ivana Šestáková2,
  3. José Manuel Díaz-Cruz1

Article first published online: 2 DEC 2005

DOI: 10.1002/elan.200503390

Issue

Electroanalysis

Electroanalysis

Volume 18, Issue 2, pages 169–176, January 2006

Additional Information

How to Cite

Serrano, N., Šestáková, I. and Díaz-Cruz, J. (2006), Constant Current Stripping Chronopotentiometry for the Study of Adsorbing Inert and Electrochemically Nonreversible Metal Complexes at Low Concentrations: Application to Cd and Zn Metallothioneins. Electroanalysis, 18: 169–176. doi: 10.1002/elan.200503390

Author Information

  1. 1

    Departament de Química Analítica, Facultat de Química, Universitat de Barcelona, Av. Diagonal 647, E-08028 Barcelona, Spain

  2. 2

    J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-18223 Prague 8, Czech Republic

Publication History

  1. Issue published online: 13 JAN 2006
  2. Article first published online: 2 DEC 2005
  3. Manuscript Received: 30 AUG 2005
  4. Manuscript Accepted: 30 AUG 2005

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Keywords:

  • Metallothionein;
  • Constant current chronopotentiometry;
  • Voltammetry

Abstract

Constant current chronopotentiometric stripping analysis using adsorptive accumulation and negative stripping current (AdSCP) was applied for the study of behavior of rabbit liver Cd-Zn and Zn metallothionein (Cd-Zn-MT, ZnMT) on hanging mercury drop electrode. Electrochemically inert or labile behavior of complexes can be distinguished with the application of high (1000 nA) or low (100 to 20 nA) current. Using high current, no influence of added Cd2+ or Zn2+ ions on the reduction of Cd(II) or Zn(II) complexed within MT molecule was observed, except of additions of Cd2+ to ZnMT, where bound Zn(II) was substituted by cadmium ions. With lowering of stripping current and increasing concentration of added Cd2+ or Zn2+ ions in solution progressive formation of reorganized complex with labile behavior is observed. Parallel measurement using DC voltammetry with different rates of polarization or differential pulse voltammetry were in agreement with AdSCP measurement. However, only chronopotentiometric method combines good sensitivity and signal separation at μM concentrations, inevitable in MT studies.

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