1. Marcio Jose da Silva, Chemistry Department, Federal University of Vicosa, University Campus, Avenue P.H. Rolfs, Vicosa, 36570-000, Minas Gerais State, Brazil
2. Castelo Bandane Vilanculo, Chemistry Department, Pedagogic University of Mozambique, FCNM, Campus of Lhanguene, Av. de Moçambique, Km 1, Maputo, Mozambique, 4040