Forensic Application of X-ray Fluorescence Spectroscopy for the Discrimination of Authentic and Counterfeit Revenue Stamps.
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.
ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas-UNICAMP, Brazil jose.perez@iqm.unicamp.br.
Jose Javier
JJ
Melendez-Perez
ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas-UNICAMP, Brazil.|Technical-Scientific Police Superintendency, Criminalistic Institute Dr. Octávio Eduardo de Brito Alvarenga -IC-SPTC-SP, São Paulo, Brazil.
Deleon Nascimento
DN
Correa
ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas-UNICAMP, Brazil.
Vinicius Veri
VV
Hernandes
ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas-UNICAMP, Brazil.
Damila Rodrigues
DR
de Morais
National Institute of Metrology, Quality and Technology-INMETRO, Rio de Janeiro, Brazil.
Rodrigo Borges
RB
de Oliveira
National Institute of Metrology, Quality and Technology-INMETRO, Rio de Janeiro, Brazil.
Wanderley
W
de Souza
ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas-UNICAMP, Brazil.
Jandyson Machado
JM
Santos
ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas-UNICAMP, Brazil.
Marcos Nogueira
MN
Eberlin
Forensic science; energy-dispersive X-ray fluorescence; questioned documents; revenue stamp; tax stamp