1. Department of Analytical Chemistry, Institute of Chemical Technology, Technická 5, 166 28 Prague 6, Czech Republic
2. Anorganische Chemie, Bergische Universität Wuppertal, Gaußstr. 20, D-42097 Wuppertal, Germany
3. Department of Chemistry, University of British Columbia, British Columbia V6T 1Z1, Canada
4. J. Heyrovský Institute of Physical Chemistry, ASCR, Dolejškova 3, 182 23 Prague 8, Czech Republic