Especiação química de arsênio em samambaia utilizando espectrometria de massas com ionização ambiente

• Ano de defesa: 2016
• Autor(a) principal: Lívia Botelho Abreu
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Especiação de arsênio; Espectrometria de massas; Samambaias; Química analítica; Arsênio Especiação química; Espectrometria de massa; Samambaia
• Link de acesso: http://hdl.handle.net/1843/SFSA-ADLQ4Y

The various chemical forms of arsenic compounds, including organic and inorganic species, exhibit different toxicities and environmental impacts. Ambient ionization mass spectrometry, such as DESI-MS (desorption electrospray ionization mass spectrometry), DESI-MSI (desorption electrospray ionization mass spectrometry imaging) and PS-MS (paper spray mass spectrometry), are excellent techniques for in situ analysis, under atmospheric pressure, at room temperature and low sample-consumption analysis to be performed with minimal sample pretreatment. These three techniques were applied for the rapid detection of inorganic compounds (arsenate - As (V) and arsenite - As (III)) and organic compounds (dimethylarsinic acid - DMA and disodium hexahydrate metilarsenate - MMA) of arsenic in fern leaves, aiming to expand applications for these techniques. Operating conditions of DESI-MS were optimized with DMA standard solution deposited on a paper surface to improve ionization efficiency. DESI-MS was applied to the fern leaves analysis artificially contaminated with As. Analyses in DESI-MSI were performed by the indirect method where the impression of fern leaf on a PTFE filter surface was made and the ions analyzed in the full scan mode. For PS-MS, fern leaf extract in methanol was placed in a triangular paper and analyzed. Mass spectra for all species of As were acquired in positive and negative ion mode and can confirm the presence of As (V) by ions of m/z 140,92, 142,93 e 160,94; As (III), by ions of m/z 106,91, 124,92, 126,94 e 144,95; DMA, by ions of m/z 138,97 e 156,98; and MMA, by ions of m/z 138,93, 140,95 e 158,96. For DESI-MS and PS-MS, MS/MS spectra were confirmed the identity of each As compound by the characteristic fragmentation profile. For the DESI-MSI, the confirmation was made by the mass error for each analyzed ion. The quantification of the As compounds by LC-ICP-MS confirmed the results obtined by three tecniques. Thus, it is possible demonstrate the applicability of the DESI-MS, DESI-MSI e PSMS as rapid, simple, efficient and with little sample preparation for detecting arsenic compounds in complex matrices.