IQ - Artigos publicados em periódicos
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Navegando IQ - Artigos publicados em periódicos por Autor "Aguiar, Deborah Victoria Alves de"
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Item Directly mapping the spatial distribution of organic compounds on mineral rock surfaces by DESI and LAESI mass spectrometry imaging(2022) Silva, Igor Pereira da; Ramalho, Ruver Rodrigues Feitosa; Maciel, Lanaia Ítala Louzeiro; Aguiar, Deborah Victoria Alves de; Gomes, Yan Trindade Lisbôa; Cruz, Georgiana Feitosa da; Vianna, Angelo Marinho; Medeiros Júnior, Iris; Lima, Gesiane da Silva; Vaz, Boniek GontijoHere, we present a new application of desorption electrospray ionization (DESI) and laser ablation electrospray ionization (LAESI) mass spectrometry imaging to assess the spatial location of organic compounds, both polar and nonpolar, directly from rock surfaces. Three carbonaceous rocks collected from an aquatic environment and a berea sandstone subjected to a small-scale oil recovery experiment were analyzed by DESI and LAESI. No rock pretreatment was required before DESI and LAESI analyses. DESI detected and spatially mapped several fatty acids and a disaccharide on the surfaces of carbonaceous rocks, and various nitrogenated and oxygenated compounds on the surfaces of berea sandstone. In contrast, LAESI using a 3.4 μm infrared laser beam was able to detect and map hydrocarbons on the surfaces of all rock samples. Both techniques can be combined to analyze polar and nonpolar compounds. DESI can be used first to detect polar compounds, as it does not destroy the rock surface, and LAESI can then be used to analyze nonpolar analytes, as it destroys a layer of the sample surface. Both techniques have the potential to be used in several scientific areas involving rocks and minerals, such as in the analysis of industry-derived contaminants in aquatic sediments or in small-scale rock–fluid interaction experiments.Item Laser ablation electrospray ionization mass spectrometry imaging as a new tool for accessing patulin diffusion in mold-infected fruits(2022) Lima, Gesiane da Silva; Santos, Gabriel Franco dos; Ramalho, Ruver Rodrigues Feitosa; Aguiar, Deborah Victoria Alves de; Roque, Jussara Valente; Maciel, Lanaia Ítala Louzeiro; Simas, Rosineide Costa; Silva, Igor Pereira da; Vaz, Boniek GontijoThis work describes the use of laser ablation electrospray ionization mass spectrometry imaging (LAESI imaging) to investigate the diffusion of the mycotoxin patulin from rotten to healthy areas of fruits. Slices of mold-infected and uninfected (control) apples and strawberries were prepared, and this was the only sample preparation step used. An infrared laser beam (2.94 μm) was used to irradiate the slices, resulting in the ablation of sample compounds directly ionized by electrospray and analyzed by mass spectrometry. Multivariate curve resolution – alternating least squares was applied in unfolded LAESI images to obtain relative quantity information. Patulin was not detected in the control samples but was seen in all mold-infected fruits. LAESI images showed the diffusion of patulin from the rotten area to unaffected parts of the fruits. This study points out the advantage of LAESI imaging over traditional analytical methods used to study the diffusion of mycotoxins in fruits.