1. Group of Biological Chemistry and Chemometrics
2. Institute of Chemistry
3. Federal University of Rio Grande do Norte
4. Natal 59072-970
5. Brazil
6. LNLS – Brazilian Synchrotron Light Laboratory CEP 13083-970
7. Campinas
8. Laboratory of Medical Bacteriology
9. Center of Biosciences
10. Natal 59078-970
11. Laboratory of Biotechnology – Labio
12. National Institute of Metrology, Quality and Technology – Inmetro
13. RJ