Nitrogen (N)-containing compounds are naturally present in petroleum, and they are responsible for several deleterious effects that reduce the quality of products and negatively affect the processes involved in the upgrading of feedstock. The speciation of such compounds in petroleum heavy fractions is still a challenge. In the present work, N-containing compounds were characterized in heavy gas oil (HGO) fractions using a solid−liquid fractionation scheme and comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry. Classification and identification of compounds were carried out based on seven different categories of analytical information viz. retention times in first and second dimensions, analytical standards co-injection, the structured pattern of the separation space, the structured pattern of the separation space with the selection of specific m/z values, the library mass spectra match factor, and the characteristic deconvoluted mass spectra. All of these interpretations were available from a single analytical run followed by a standard injection. Compounds were extracted from the sample using an ion-exchange resin method to separate neutral and basic N-containing compounds, after a pre-fractionation step, using neutral aluminum oxide. This methodology allowed for the identification of 120 N-containing compounds and tentative identification of a further 108 compounds using their deconvoluted characteristic mass spectra as a basis for identification. Identified components included alkyl-indols, alkyl-carbazols, alkyl-benzocarbazols, alkyl-quinolines, alkyl-indene-pyridines, alkyl-benzoquinolines, and alkyl-dibenzoquinolines.

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Qualitative and quantitative study of nitrogencontaining compounds in heavy gas oil using comprehensive two-dimensional gas chromatography with nitrogen phosphorus detectionIn this work, a GC6GC -nitrogen -phosphorus detection (NPD) methodology was developed to separate and quantitate nitrogen-containing compounds in Brazilian heavy gas oil. First, the NPD performance was improved in order to achieve best GC6GC performance. The geometry of this detector was also evaluated. The use of an extended jet improved significantly the peak shape. The GC6GC separation was studied using both first and second dimension columns with different internal diameters. The use of a thicker film in both dimensions provided better performance. LODs of 0.16 -8.49 pg of individual compounds were achieved. Two different extraction techniques of the neutral and basic nitrogen-containing compounds were also evaluated. The method using ion-exchange resins to separate neutral and basic nitrogen-containing compounds was more efficient than the method using modified silica. As an example, the amounts (lg/g) of each class reported were: indole (2.77), alkyl carbazoles ranging from C 0 to C 6+ (1.467), alkyl benzocarbazoles from C 0 to C 4+ (793), alkyl quinolines (31.2) and alkyl benzoquinolines (21.6) were quantitated.

Um dos maiores desafios enfrentados pelas presentes e futuras gerações é encontrar formas de preservação das fontes de água, livres de contaminações e adequadas ao consumo da população. Essa dificuldade está relacionada à contaminação dos lençóis freáticos devido à ocupação e uso do solo pela sociedade, alterando os processos físicos, químicos e biológicos dos sistemas naturais, causando inúmeras doenças e muitas vezes levando a morte. O presente trabalho objetivou avaliar a qualidade da água das principais fontes naturais do município de Imigrante, localizado no Vale do Taquari-RS a fim de averiguar a potabilidade das águas consumidas pelas comunidades do município. Na presente pesquisa foram selecionados dez poços para a verificação das características físico-químicas e biológicas, tais como: pH, condutividade, sólidos suspensos, turbidez, oxigênio dissolvido, carbono orgânico, carbono total, carbono inorgânico, nitrogênio, dureza média, temperatura, condutividade e análise microbiológica, comparando os resultados com os padrões preestabelecidos pela legislação vigente. Dos dez poços analisados, seis apresentaram-se fora dos parâmetros estabelecidos pela legislação. Este é o caso dos níveis de turbidez, colorimetria, sólidos totais, nitrato, Coliformes totais e Escherichia coli, parâmetros que em excesso tornam imprópria a água para o consumo com efeitos sobre sua palatabilidade, conferindo propriedades laxantes e mesmo, indiretamente, indicar a presença de patógenos que podem ter graves repercussões sobre a saúde. Assim, este estudo destaca a necessidade de utilizar os métodos de desinfecção de água de poços antes de seu consumo.

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