1. School of Chemistry and Physics, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, South Africa
2. Department of Mathematics and Physical Sciences, Maasai Mara University, Narok, Kenya
3. Department of Pure and Applied Chemistry, School of Natural Sciences, Masinde Muliro University of Science and Technology, Kakamega, Kenya
4. Department of Chemistry, Maseno University, Maseno, Kenya
5. School of Pure and Applied Sciences, Mount Kenya University, Thika, Kenya
6. Faculty of Applied Sciences, Department of Chemistry, Durban University of Technology, Durban, South Africa