Documentoscopia por microespectroscopia Raman e microscopia de força atômica
Nenhuma Miniatura disponível
Data
2015-08-21
Autores
Brandão, Jandira Maria de Oliveira Bone
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal do Espírito Santo
Resumo
Considering the strong social and financial impact caused by document forgery, especially banknote, and the diversity of methods used in the forgeries, their increasing spread and sophistication, it is necessary to develop new methods for document analysis that are sensitive and non-destructive, because the material examined must be preserved in its entirety for continuity of legal proceedings. The objective of this study was to develop a methodology using the techniques of Microspectroscopy Raman and Atomic Force Microscopy, which allows to distinguish the authentic documents of counterfeit, and to determine the means employed in the forgery, that is reliable, with low analysis time and undamaged the samples. This study used authentic and counterfeit banknotes of R$ 100.00 and CNH, authentic dollar banknotes of different values ($ 10.00 and $ 20.00), and authentic banknotes of € 5.00 from different manufacturers; for each sample type (authentic and counterfeit) were used three different copies. All analyzes were performed in situ without any surface preparation, using confocal microscope Alpha 300R WITEC of NCQP / UFES coupled with Raman microspectroscope and atomic force microscope, being selected the same regions in both the authentic and counterfeit documents. The study divided into two parts. The first part dealt with the analysis of samples using AFM, by assessing the topography parameters, phase and roughness of the different papers used in manufacturing these documents. The results obtained by AFM could differentiate the authentic documents (with smoother surfaces and topographical regions characteristics for the security features) of counterfeit (over uneven surfaces and similar topographic profile in all regions), discriminate the type of paper used for forgery (physicochemical properties similar to Office type paper), and also distinguish between authentic banknotes produced by different manufacturers (difference between SSK and SKU values). In the second part, we addressed the analysis of samples using RM, through the identification of pigments used in the preparation of various documents. The results obtained by RM possible to distinguish authentic documents (with a predominance of characteristic peaks for the carbon black, copper phthalocyanine, diarylide and titanium dioxide), of counterfeit (predominantly fluorescence and calcium carbonate bands characteristic of the commercial paper treatment), and identify the type of printing used in the forgeries. The combination of the two techniques has shown promise for the forensic analysis of documents because it provides accurate and reproducible results in a short time and, above all, without prejudice to the analyzed material.
Descrição
Palavras-chave
Forgery , Forensic , Atomic force microscopy , Raman microspectroscopy banknote , Forense
Citação
BRANDÃO, Jandira Maria de Oliveira Bone. Documentoscopia por microespectroscopia Raman e microscopia de força atômica. 2015. Dissertação (Mestrado em Química) – Universidade Federal do Espírito Santo, Vitória, 2015.