Direct and non-destructive proof of authenticity for the 2nd generation of Brazilian real banknotes via easy ambient sonic spray ionization mass spectrometry

Eduardo Morgado Schmidt; Marcos Fernando Franco; Karen Gomes Regino; Eraldo Luiz Lehmann; Marco Aurélio Zezzi Arruda; Werickson Fortunato de Carvalho Rocha; Rodrigo Borges; Wanderley de Souza; Marcos Nogueira Eberlin; Deleon Nascimento Correa

doi:10.1016/j.scijus.2014.08.001

Direct and non-destructive proof of authenticity for the 2nd generation of Brazilian real banknotes via easy ambient sonic spray ionization mass spectrometry

Sci Justice. 2014 Dec;54(6):459-64. doi: 10.1016/j.scijus.2014.08.001. Epub 2014 Sep 13.

Affiliations

¹ ThoMSon Mass Spectrometry Laboratory, Department of Analytical Chemistry, Institute of Chemistry, University of Campinas-UNICAMP, 13083-970 Campinas, SP, Brazil.
² Group of Spectrometry, Sample Preparation and Mechanization-GEPAM, Department of Analytical Chemistry, Institute of Chemistry, University of Campinas-UNICAMP, 13083-970 Campinas, SP, Brazil.
³ National Institute of Metrology, Quality and Technology-INMETRO, 25250-020, Rio de Janeiro, RJ, Brazil.
⁴ ThoMSon Mass Spectrometry Laboratory, Department of Analytical Chemistry, Institute of Chemistry, University of Campinas-UNICAMP, 13083-970 Campinas, SP, Brazil; Technical-Scientific Police Superintendency, Criminalistic Institute Dr. Octávio Eduardo de Brito Alvarenga-IC-SPTC-SP, 05507-06, São Paulo, SP, Brazil. Electronic address: deleon.correa@iqm.unicamp.br.

PMID: 25498934
DOI: 10.1016/j.scijus.2014.08.001

Abstract

Using a desorption/ionization technique, easy ambient sonic-spray ionization coupled to mass spectrometry (EASI-MS), documents related to the 2nd generation of Brazilian Real currency (R$) were screened in the positive ion mode for authenticity based on chemical profiles obtained directly from the banknote surface. Characteristic profiles were observed for authentic, seized suspect counterfeit and counterfeited homemade banknotes from inkjet and laserjet printers. The chemicals in the authentic banknotes' surface were detected via a few minor sets of ions, namely from the plasticizers bis(2-ethylhexyl)phthalate (DEHP) and dibutyl phthalate (DBP), most likely related to the official offset printing process, and other common quaternary ammonium cations, presenting a similar chemical profile to 1st-generation R$. The seized suspect counterfeit banknotes, however, displayed abundant diagnostic ions in the m/z 400-800 range due to the presence of oligomers. High-accuracy FT-ICR MS analysis enabled molecular formula assignment for each ion. The ions were separated by 44 m/z, which enabled their characterization as Surfynol® 4XX (S4XX, XX=40, 65, and 85), wherein increasing XX values indicate increasing amounts of ethoxylation on a backbone of 2,4,7,9-tetramethyl-5-decyne-4,7-diol (Surfynol® 104). Sodiated triethylene glycol monobutyl ether (TBG) of m/z 229 (C10H22O4Na) was also identified in the seized counterfeit banknotes via EASI(+) FT-ICR MS. Surfynol® and TBG are constituents of inks used for inkjet printing.

Keywords: Ambient mass spectrometry; Easy ambient sonic-spray ionization mass spectrometry; Forensic science; Questioned documents.