1. Department of Chemistry, Higher Teacher Training College, The University of Bamenda, P.O. Box 39, Bambili, Cameroon
2. Department of Chemistry, Faculty of Sciences, University of Douala, P.O. Box 24157, Douala, Cameroon
3. Department of Chemistry and Industrial Chemistry, Kwara State University, Malete, P.M.B 1530, Ilorin 23431, Nigeria