A carregar...
Publicação
Análise e caracterização de tintas de escrita por LC-MS
| Nome: | Descrição: | Tamanho: | Formato: | |
|---|---|---|---|---|
| 2.68 MB | Adobe PDF |
Autores
Resumo(s)
No âmbito das ciências forenses, a análise documental é a ciência que permite o estudo, a análise e a
investigação dos documentos, com o objetivo de determinar, entre outros, a sua autenticidade ou
falsidade para fins judiciais, recorrendo no seu processo a metodologias e instrumentação apropriada.
Atualmente, são relatados milhares de casos de falsificação e contrafação de documentos ao redor do
mundo, levando ao aumento de danos secundários a nível económico numa escala global. Assim sendo,
é de extrema importância que as empresas, quando aceitem documentos, analisem a veracidade dos
mesmos antes de aprová-los. Dos crimes existentes para a falsificação e contrafação, encontram-se
roubos, neglicência médica, fraude financeira e económica, terrorismo, homicídios e tráfico de drogas,
de veículos, de armas e de pessoas.
Dado isto, a análise forense de tintas é fundamental para fornecer evidências valiosas na resolução de
vários tipos de crimes, pois esta envolve a classificação e identificação dos diferentes constituintes
presentes nas tintas.
Neste estudo, recorreu-se à cromatografia líquida acoplada à espetrometria de massa de alta resolução
(LC-Orbitrap MS) para análise e caracterização dos corantes presentes nas tintas de instrumentos de
escrita de cor azul e preta nomeadamente esferográficas. Para tal, foram analisadas 40 amostras de tinta
de esferográficas, provenientes de 19 marcas diferentes amplamente usadas no mercado nacional e
internacional. Os espectros de massa foram submetidos à análise de agrupamento hierárquico (HCA) e
à análise de componentes principais (PCA), permitindo agrupar esferográficas da mesma marca e
aproximar aquelas de marcas distintas, mas apresentando composições químicas similares. Além disso,
essas análises também evidenciaram esferográficas com formulações significativamente diferentes das
demais. Apesar de algumas limitações no método aplicado, foi possível detetar e identificar os corantes
presentes nas esferográficas de cor azul e preta, bem como identificar semelhanças e diferenças entre as
marcas analisadas.
In the field of forensic science, document analysis is the science that enables the study, examination, and investigation of documents with the aim of determining, among other things, their authenticity or falsity for judicial purposes, using appropriate methodologies and instrumentation in the process. Currently, thousands of cases of document forgery and counterfeiting are reported worldwide, leading to increased secondary economic damage on a global scale. Therefore, it is of utmost importance that companies, when accepting documents, verify their authenticity before approving them. Crimes associated with forgery and counterfeiting include theft, medical negligence, financial and economic fraud, terrorism, homicide, and trafficking of drugs, vehicles, weapons, and people. Given this, forensic ink analysis is essential for providing valuable evidence in the resolution of various types of crimes, as it involves the classification and identification of different components present in inks. In this study, liquid chromatography coupled with high-resolution mass spectrometry (LC-Orbitrap MS) was used to analyze and characterize the dyes present in blue and black ink pens, particularly ballpoint pens. For this purpose, 40 ink samples from ballpoint pens, from 19 different brands widely used in national and international markets, were analyzed. The mass spectra were subjected to hierarchical clustering analysis (HCA) and principal component analysis (PCA), allowing for the grouping of pens from the same brand and the clustering of pens from different brands with similar chemical compositions. Additionally, these analyses revealed pens with significantly different formulations. Despite some limitations in the method applied, it was possible to detect and identify the dyes present in blue and black ballpoint pens, as well as to identify similarities and differences among the brands analyzed.
In the field of forensic science, document analysis is the science that enables the study, examination, and investigation of documents with the aim of determining, among other things, their authenticity or falsity for judicial purposes, using appropriate methodologies and instrumentation in the process. Currently, thousands of cases of document forgery and counterfeiting are reported worldwide, leading to increased secondary economic damage on a global scale. Therefore, it is of utmost importance that companies, when accepting documents, verify their authenticity before approving them. Crimes associated with forgery and counterfeiting include theft, medical negligence, financial and economic fraud, terrorism, homicide, and trafficking of drugs, vehicles, weapons, and people. Given this, forensic ink analysis is essential for providing valuable evidence in the resolution of various types of crimes, as it involves the classification and identification of different components present in inks. In this study, liquid chromatography coupled with high-resolution mass spectrometry (LC-Orbitrap MS) was used to analyze and characterize the dyes present in blue and black ink pens, particularly ballpoint pens. For this purpose, 40 ink samples from ballpoint pens, from 19 different brands widely used in national and international markets, were analyzed. The mass spectra were subjected to hierarchical clustering analysis (HCA) and principal component analysis (PCA), allowing for the grouping of pens from the same brand and the clustering of pens from different brands with similar chemical compositions. Additionally, these analyses revealed pens with significantly different formulations. Despite some limitations in the method applied, it was possible to detect and identify the dyes present in blue and black ballpoint pens, as well as to identify similarities and differences among the brands analyzed.
Descrição
Tese de Mestrado, Química, 2024, Universidade de Lisboa, Faculdade de Ciências
Palavras-chave
LC-Orbitrap MS Esferográficas Análise multivariada Corantes e documentoscopia Teses de mestrado - 2024