**Author details**

Novisi K. Oklu, Leah C. Matsinha and Banothile C.E. Makhubela\* Department of Chemical Sciences, University of Johannesburg, Johannesburg, South Africa

\*Address all correspondence to: bmakhubela@uj.ac.za

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
