1. ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry; University of Campinas; UNICAMP 13083-970; Campinas; SP; Brazil
2. University of São Paulo; Institute of Chemistry; Av. Prof. Lineu Prestes 748; CEP 05508-000; São Paulo; SP; Brazil
3. National Institute of Metrology, INMETRO; Division of Chemical Metrology 25250-020; Duque de Caxias; RJ; Brazil
4. Federal University of Sergipe; Department of Chemistry; CEP 49500-000; Itabaiana; SE; Brazil
5. 26 Twyniago, Pontarddulais; Swansea; SA4 8HX; U.K.