1. Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
2. Department of Chemistry, Faculty of Science, Ain Shams University, Abbassia, Cairo 11566, Egypt
3. Centre for Teaching, Learning and Technology, National University of Singapore, 15 Kent Ridge Road, Singapore 119225, Singapore
4. College of Humanities and Sciences, National University of Singapore, 21 Lower Kent Ridge Road, Singapore 119077, Singapore
5. NUS Environmental Research Institute (NERI), #02-01, T-Lab Building (TL), 5A Engineering Drive 1, Singapore 117411, Singapore