1. Department of Chemistry, University of Nairobi, Nairobi, Kenya
2. Institute of Environmental Research (INFU), Department of Chemistry and Chemical Biology, Chair of Environmental Chemistry and Analytical Chemistry, TU Dortmund, Dortmund, Germany
3. Department of Chemistry, Busitema University, Tororo, Uganda
4. Department of Chemistry, Addis Ababa University, Addis Ababa, Ethiopia
5. School of Biological Sciences, University of Nairobi, Nairobi, Kenya