1. Physical Organic Chemistry Laboratory, Institute of Chemistry, Universidade Estadual de Campinas, UNICAMP, PO Box 6154, Campinas 13083-970, São Paulo, Brazil
2. Spectrometry, Sample Preparation and Mechanization Group, Institute of Chemistry, Universidade Estadual de Campinas, UNICAMP, PO Box 6154, Campinas 13083-970, São Paulo, Brazil
3. Laboratory of Plant Anatomy, Institute of Biology, Universidade Estadual de Campinas, UNICAMP, PO Box 6109, Campinas 13083-862, São Paulo, Brazil
4. Institute of Chemistry, Universidade Estadual de Campinas, UNICAMP, PO Box 6154, Campinas 13083-970, São Paulo, Brazil