1. University of Lodz, Faculty of ChemistryDepartment of Inorganic and Analytical Chemistry Tamka 12 91-403 Lodz Poland
2. Charles University, Faculty of Science, Department of Analytical ChemistryUNESCO Laboratory of Environmental Electrochemistry Albertov 6 CZ-12843 Prague 2 Czech Republic
3. Ss. Cyril and Methodius University, Faculty of Natural Sciences and MathematicsInstitute of Chemistry Arhimedova 5, P.O. Box 162 1001 Skopje R. Macedonia