Técnicas de análise direta em espectrometria de massas: soluções simples para complexas questões da química de produtos naturais à análise forense
Data
2020-08-04
Autores
Bronzel Junior, João Luiz
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Atualmente, a espectrometria de massas é uma das técnicas analíticas de maior destaque em diversos campos de aplicação. As modernas técnicas de ionização apresentam grande versatilidade, permitindo a análise direta de várias matrizes complexas. Dentre elas, destacam-se as técnicas de ionização por paper spray (Paper Spray Ionization - PSI), e a ionização por tissue spray (Tissue Spray Ionization -TSI), as quais apresentam como principais vantagens a simplicidade no preparo de amostras, a rapidez da análise e o baixo consumo de solventes, conceitos que apresentam-se alinhados a alguns dos princípios da química analítica verde. Nesse trabalho a técnica de análise direta TSI-MS foi utilizada para mapear a via biossintética dos alcaloides indólicos terpenoídicos (AITs) em folhas e flores de Catharanthus roseus. Esse estudo resultou na detecção de vários produtos finais dessa via, com destaque para serpentina, alstonina, vindolinina e seu epímero 19-S-vindolinina, 3,4- anidrovinblastina e vimblastina. Além disso, foi possível identificar o alcaloide bisindólico serpentinina, o que resultou no primeiro relato dessa substância em flores de Catharanthus roseus. Essa mesma técnica também foi utilizada no estudo das variações metabólicas em Citrus sinensis var. Valência causadas pela infecção por Candidatus Liberibacter asiaticus, bactéria causadora da enfermidade denominada HLB, comumente conhecida como greening de Citrus, que afeta diretamente a produção de laranja. Nessa investigação foi possível detectar um maior teor do aminoácido arginina nas folhas de indivíduos infectados. Sob o ponto de vista biossintético, foi possível estabelecer a correlação entre o aumento da produção desse aminoácido a algumas respostas metabólicas atribuídas à defesa da planta. Ainda no âmbito desse trabalho, membranas de poliamida 66 foram utilizadas como fase estacionária em cromatografia planar acoplada à espectrometria de massas pela técnica de PSI, no desenvolvimento de uma metodologia simples, rápida e sustentável para identificação de corantes utilizados na composição de tintas de canetas esferográficas. O método desenvolvido foi aplicado com êxito na detecção de adulterações em documentos, sem prejudicar a interpretação da escrita após a realização das análises.
Nowadays, mass spectrometry is one of the most prominent analytical techniques in several application fields. Modern ionization techniques have great versatility, allowing direct analysis of several complex matrices. Among them, paper spray ionization (PSI) and tissue spray ionization (TSI) stand out, because of their main advantages like sample preparation simplicity, the rapidity of analysis and low solvent consumption, concepts which are aligned with some principles of green analytical chemistry. In this work, TSI-MS direct analysis technique was used to map the biosynthetic pathway of terpenoid indolic alkaloids (TIAs) in leaves and flowers of Catharanthus roseus. This study resulted in the detection of several final products of this route, with emphasis on serpentine, alstonine, vindolinine and its epimer 19-S-vindolinine, 3,4- anhydrovinblastine and vinblastine. In addition, it was possible to identify the bisindolic alkaloid serpentinine, which resulted in the first report of this substance in Catharanthus roseus flowers. TSI-MS was also used to study metabolic variations in Citrus sinensis var. Valencia, caused by infection with Candidatus Liberibacter asiaticus, a bacterium that causes the disease called HLB, commonly known as Citrus greening, which directly affects orange production. In this investigation it was possible to detect a higher concentration of the amino acid arginine in leaves of infected plants. From biosynthetic point of view, it was possible to establish a correlation between the increase in the production of this amino acid and some metabolic responses attributed to plant defense. Still within the scope of this work, polyamide 66 membranes were used as a stationary phase in planar chromatography coupled to mass spectrometry by the PSI-MS technique in the development of a simple, fast and sustainable methodology for identifying dyes used in the composition of ballpoint pen inks. The developed method was successfully used to detect adulteration in documents, without impairing the interpretation of the writing after analysis.
Nowadays, mass spectrometry is one of the most prominent analytical techniques in several application fields. Modern ionization techniques have great versatility, allowing direct analysis of several complex matrices. Among them, paper spray ionization (PSI) and tissue spray ionization (TSI) stand out, because of their main advantages like sample preparation simplicity, the rapidity of analysis and low solvent consumption, concepts which are aligned with some principles of green analytical chemistry. In this work, TSI-MS direct analysis technique was used to map the biosynthetic pathway of terpenoid indolic alkaloids (TIAs) in leaves and flowers of Catharanthus roseus. This study resulted in the detection of several final products of this route, with emphasis on serpentine, alstonine, vindolinine and its epimer 19-S-vindolinine, 3,4- anhydrovinblastine and vinblastine. In addition, it was possible to identify the bisindolic alkaloid serpentinine, which resulted in the first report of this substance in Catharanthus roseus flowers. TSI-MS was also used to study metabolic variations in Citrus sinensis var. Valencia, caused by infection with Candidatus Liberibacter asiaticus, a bacterium that causes the disease called HLB, commonly known as Citrus greening, which directly affects orange production. In this investigation it was possible to detect a higher concentration of the amino acid arginine in leaves of infected plants. From biosynthetic point of view, it was possible to establish a correlation between the increase in the production of this amino acid and some metabolic responses attributed to plant defense. Still within the scope of this work, polyamide 66 membranes were used as a stationary phase in planar chromatography coupled to mass spectrometry by the PSI-MS technique in the development of a simple, fast and sustainable methodology for identifying dyes used in the composition of ballpoint pen inks. The developed method was successfully used to detect adulteration in documents, without impairing the interpretation of the writing after analysis.
Descrição
Palavras-chave
Espectrometria de massas, Produtos naturais, Biossíntese, Fitopatologia, Química forense, Mass spectrometry, Natural products, Biosynthesis, Phytopathology, Forensic chemistry