Silva, Marta Filomena de Sousa, 1975-Carvalho, Áurea Marília Madureira ePereira, Mariana Vieira2023-06-012023-12-3120232022http://hdl.handle.net/10451/57807Tese de mestrado, Química (Química), 2022, Universidade de Lisboa, Faculdade de CiênciasFingerprints are unique to each individual and commonly correspond to a complex pattern of ridges and valleys, crucial in Forensic Sciences for human identification. Throughout the years, this has been one of the methods used in criminal investigations to place a suspect at a crime scene. However, this method depends on the integrity of the fingermark, on the method used for its recovery, and if the respective fingerprint is listed or not at the National/International Fingerprint Database. However, the ridge pattern does not present all available human information. Most notably, the chemical signature that is left behind, composed by endogenous, exogenous and semi-endogenous compounds, are of great forensic importance. Until now, human fingermarks have been mainly chemically analysed by low resolution mass spectrometry methods. The first mass spectrometry technique used to study the fingerprint’s composition was Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (MALDI MS). With this technique, not only a fingerprint’s image is obtained, which may be used in a biometric identification, but it is also possible to profile the fingerprint’s chemical composition. However, this type of approach is not adequate to make a thorough characterization of small molecules, with hundreds to thousands of metabolites detected. Another drawback in studying latent fingermarks chemical composition, is their development with different reagents, making their characterization, by mass spectrometry, an extremely complex affair in a realistic scenario. Aiming an untargeted metabolomics approach to study the chemical composition in fingermarks, this work was performed using the most extreme resolution and mass accuracy technique available, Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS), enabling the detailed description of the chemical complexity of dermo papillary residues and leading to the identification of hundreds of chemical species and metabolites. Another purpose of this study was to obtain relevant chemical information from fingermarks in the presence of common fingermark developers like Instant White, Magnetic Latent Print Powder and Dragon’s Blood. In the optimization tests the Magnetic Latent Print Powder proved that is not compatible with the analysis of fingermark residue by FT-ICR MS. The study was performed with fingermarks of some volunteers, sex balanced and within two age groups (18 - 30 years and 31 - 60 years), analysed by combining accurate mass measurements using FT-ICR MS, database search like Human Metabolome Database (HMDB) and molecular formula determination. Similarities between volunteers samples were identified by building Principal Component Analysis (PCA) and Hierarchical Clustering Analysis (HCA) models. Sex and age discriminating compounds were identified by building Partial Least Squares – Discriminant Analysis (PLS-DA) models. With a small subset of samples with minor age ranges (20 – 30 years and 45 – 55 years), it was possible to discriminate fingermarks by sex and age, where the fingermark developing powders did not considerably affect the dermo papillary residue composition, since the chemical composition of developed and non-developed samples was very similar. Several annotated compounds from this group were obtained, most of them being lipids, mainly fatty acyls, glycerolipids, prenol lipids and sphingolipids. In the analysis of all collected samples, the discrimination between sex and age was more difficult due to similarities in the daily habits of individuals. Although it was not possible the identification of chemical biomarkers of current daily habits or related with the medication taken by the volunteers, it was possible the identification of some metabolites (hexadecasphinganine, phytosphingosine and sphinganine) that most contribute for the discrimination of sex and age groups. Therefore, the use of FT-ICR MS has proven to be a powerful analytical technique for studying the chemical signature of fingermarks due to its unmatched resolution, mass accuracy and sensitivity for detecting any type of molecules, which could give an important contribution to Forensic Sciences.engForenseImpressões digitaisPós de revelação de impressões digitaisEspectrometria de massa de ressonância ciclotrónica de ião com transformada de FourierMetabolómicaTeses de mestrado - 2023master thesis203492978