Abordagens multidimensionais avançadas para a caracterização de poluentes ambientais usando GC×GC/Q-TOFMS

Abstract

This thesis presents three innovative studies in environmental health using the advanced technique of comprehensive two-dimensional gas chromatography coupled with hybrid quadrupole time-of-flight mass spectrometer (GC×GC/Q-TOFMS). In the first study, an analytical method based on GC×GC/Q-TOFMS, using propyl chloroformate/propanol derivatization, was developed and validated for the analysis (untargeted and targeted) of metabolites in samples of human skin fibroblast cell extracts exposed to the herbicide Roundup®. The untargeted approach allowed the identification of 379 compounds from diverse metabolic classes, including fatty acids, alcohols, hydrocarbons, ketones, aldehydes, amines, and amides, while the targeted strategy quantified 21 amino acids with high specificity. Data analysis revealed a panel of 7 highly discriminatory potential biomarkers: methylcysteine and N-acetyl-L-methionine (alterations in sulfur metabolism), methyl stearate and linoleic acid (lipid dysfunction), L-glutamic acid, L-cysteine and γ-aminobutyric acid (GABA) (neurotransmitter dysregulation). The identification of GABA and lipid intermediates suggested toxicological mechanisms associated with oxidative stress and neurotoxicity, in line with recent studies on the impact of glyphosate on critical metabolic pathways. In the second study, a high-resolution analytical method based on GC×GC, using direct immersion solidphase microextraction (DI-SPME), was developed for untargeted analysis of particulate matter (PTS and PM2.5). The samples were collected in Brumadinho/MG after the collapse of the mining tailings dam in Córrego do Feijão. The study identified 382 organic compounds in the atmospheric samples, covering classes of critical toxicity for human health, such as pesticides, polycyclic aromatic hydrocarbons (PAHs), and other volatile organic compounds (VOCs). The results constituted the first robust analytical evidence of post-failure atmospheric contamination, catalyzing emergency actions. Finally, the third work consisted of applying design of experiments and optimization tools in developing a GC×GC method for untargeted analysis of particulate matter (PM2.5) collected in Belo Horizonte/Minas Gerais, using DI-SPME extraction. The study investigated contrasts in air contamination between two regions of Belo Horizonte: a predominantly forested region (UFMG Ecological Park), considered a reference for low anthropogenic impact, and another in an urban area with high vehicle density (UFMG Entrance 1, located on Antônio Carlos Avenue). Using GC×GC/Q-TOFMS, 189 volatile and semivolatile organic compounds were identified in the collected samples. Among these, plasticizers and PAH derivatives stood out. The results indicated atmospheric transport of pollutants from the urban area to natural regions of Belo Horizonte, such as the UFMG Ecological Park. The results expose the vulnerability of urban ecosystems to atmospheric dynamics, where protected areas suffer infiltration of pollutants from vehicular and industrial sources.