1. Department of Chemistry, Delta State University, Abraka, Nigeria;
2. Department of Chemistry, University of Africa, Toru-Orua, Nigeria;
3. Department of Chemistry, Federal University of Petroleum Resources, Effurun, Nigeria;
4. Environment and Quality Control Department, Nigeria Agip Oil Company, Port Harcourt, Nigeria;
5. School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa