Banca de DEFESA: KAUANNY BEATRIZ DO NASCIMENTO BRAGA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : KAUANNY BEATRIZ DO NASCIMENTO BRAGA
DATE: 28/02/2024
TIME: 14:00
LOCAL: Em ambiente virtual (Google meet)
TITLE:

DEVELOPMENT OF METHODS FOR DATING PEN INKS IN DOCUMENTS FOR FORENSIC APPLICATIONS

KEY WORDS:

Forensic chemistry, documentscopy, ink dating, infrared spectroscopy, mass spectrometry, DESI-MS, data fusion.

PAGES: 64
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Analítica
SPECIALTY: Instrumentação Analítica
SUMMARY:

Forensic chemistry connects science with justice, applying scientific techniques and methodologies that help in the search for information and the elucidation of crimes committed through the identification of different types of chemical compounds, thus facilitating criminal investigations. Among the different areas that make up forensic chemistry, documentscopy is of great importance, since it is responsible for providing historical information on a document and assessing its veracity for judicial purposes, for example, when attempting to date pen writing. This study aimed to develop a rapid and direct method for dating pen ink on documents, using a combination of Fourier transform infrared spectroscopy in attenuated reflectance mode (FTIR-ATR), desorption electrospray ionization mass spectrometry (DESI-MS) and multiple ensemble data modeling. Two sets of paper document samples containing blue pen writing were investigated: I) artificially aged documents and II) real documents dating from 1960 to 2022. The FTIR-ATR spectra of both sets of samples showed a decrease in absorbance at ~1584 cm^-1, related to the chemical modification of the C=N bond in the molecular structure of Basic Violet 3 (BV3), one of the main dyes used in blue pen ink. DESI-MS confirmed the presence of BV3 and its degradation ions in all the samples, indicating its widespread use in the production of blue pen ink. In addition, DESI-MS detected combinations of dyes in the ink composition and it was also possible to identify the DG dye (1,3-dimethyl-1,3-dithiolylguanidine). The models were created using the DESI-MS and FTIR-ATR data separately, but the error was significantly reduced when both sets of data were used. The combination of DESI-MS and FTIR-ATR spectral information resulted in a final predictive model with low error (±5 years) for pen inks from real documents in writing from the years 1960 to 2022. These analyses proved to be effective for the dating of pen inks and are suitable for use in routine forensic analysis, providing a direct and rapid method that allows accurate prediction.

COMMITTEE MEMBERS:
Presidente - JANDYSON MACHADO SANTOS
Interno - ANDRE FERNANDO LAVORANTE
Externo à Instituição - RICARDO SALDANHA HONORATO