1. Department of Chemistry, University of Fort Hare, Alice Campus, Alice, Eastern Cape, South Africa
2. School of Pharmacy, University of the Western Cape, Bellville, Cape Town 7535, South Africa
3. School of Chemistry, Mass Spectrometry Division, University of Witwatersrand, Johannesburg, South Africa
4. Department of Chemistry, University of Johannesburg, Auckland Park Campus, Johannesburg, South Africa
5. Department of Biochemistry, Microbiology and Biotechnology, Faculty of Science and Agriculture, University of Limpopo, South Africa
6. Department of Applied Chemistry, University of Johannesburg, Doornfontein Campus, Johannesburg, South Africa