No abstract

INTRODUÇÃOAs plantas medicinais são freqüentemente utilizadas com o intuito de substituir ou auxiliar as terapias convencionais no tratamento de várias doenças. Entre outros fatores, a preferência na utilização das plantas medicinais decorre da facilidade de obtenção e do baixo custo. Porém, sabe-se que as plantas medicinais apresentam ampla diversidade de metabólitos secundários com diferentes atividades biológicas (Farnsworth et al., 1985;Simões et al., 2003), justificando a necessidade de um aprofundamento no conhecimento das propriedades farmacológicas das espécies vegetais e suas possíveis utilizações no desenvolvimento de medicamentos.Apesar da preferência das grandes indústrias farmacêuticas pelo desenvolvimento de medicamentos pela via sintética, nas últimas décadas observa-se ainda grande in-

Energy-dispersive X-ray fluorescence (ED-XRF) spectroscopy with data treatment via chemometric tools was explored as an analytical protocol to discriminate between authentic and counterfeit revenue stamps. Untreated samples were directly analyzed, and the discrimination was based on the characterization of constituent elements present in the inks and paper. Authentic samples and samples that were suspected of being counterfeit were analyzed at three different areas on their surfaces: the ink-printed area, the non-printed area, and the holographic area. Principal component analysis (PCA) was applied to the data to discriminate between authentic and counterfeit revenue stamps. Major differences in the elemental composition were noted (according to chemometrics and t-test, p < 0.05), and ED-XRF spectroscopy plus PCA protocol is proposed for use by non-specialist operators to screen for counterfeit stamps.

No abstract