Affiliation: | 1. Department of Chemistry, Higher Teachers'' Training College, University of Yaounde I, P. O. Box 47, Yaounde, Cameroon;2. Institute of Environmental Research (INFU) of the Faculty of Chemistry and Chemical Biology, Chair of Environmental Chemistry and Analytical Chemistry, TU Dortmund, Otto-Hahn-Str. 6, D-44221 Dortmund, Germany |