Emprego do dietilditiofosfato de amônio para separação da matriz e pré-concentração do analito em sistema FI-ICP-MS /

Tese (Doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico

Concentrações Anômalas de Flúor em Águas Subterrâneas

It is believed that concentrations up to 1.5 mg/L of fluorine in the waters are beneficial to human health in the prevention of dental caries in children. But higher values would be harmful and cause stains on teeth, dental fluorosis, and deformed bones. Through the literature review, it was noted that anomalous values of this element occur in crystalline, porous and karstic aquifers. The aim of this paper was to present an evolution of knowledge regarding fluoride anomalous concentrations, performing a case study on the Guarani Aquifer System/GAS. Locally the groundwater has high fluoride concentration in many Brazilian states above standards for human consumption. Many hypotheses were seeking to clarify the origin of these concentrations. However, there is still no consensus among researchers. There is a good relationship with sodic waters character, sulfated and/or chlorinated. Recent studies suggest an association with more saline, thermal waters in confined areas, associating the origin of fluoride to pre–SGA formations, carriers of salts and sulfated minerals. The most consensual hypothesis suggests the existence of mixtures with saline deep waters, indicating that there are areas where vertical flows predominate in relation to the horizontal at the GAS associated this natural process with the ion exchange capacity of the clay minerals.http://dx.doi.org/10.5902/2179460X13457Acredita-se que concentrações até 1,5 mg/L de flúor nas águas seja benéfico a saúde humana na prevenção de cáries dentárias de crianças. Porém valores superiores seriam prejudiciais, podendo causar manchas nos dentes, fluorose dental, e deformação dos ossos. Através da revisão da literatura observou-se que valores anômalos desse elemento ocorrem em aquíferos cristalinos, porosos e cársticos. O objetivo da presente pesquisa foi apresentar uma evolução dos conhecimentos em relação às concentrações anômalas de flúor em águas subterrâneas, fornecendo uma visão global, nacional, regional apresentando aportes ao conhecimento do Sistema Aquífero Guarani/SAG no Estado do Rio Grande do Sul. Esse sistema apresenta, localmente, águas com concentrações anômalas de flúor, em vários estados brasileiros acima dos padrões de consumo humano. Muitas hipóteses foram levantadas até o presente momento buscando esclarecer a origem destas concentrações. Porém, ainda não existe um consenso entre os pesquisadores. Observou-se uma boa relação espacial de com águas de caráter sódico, sulfatadas e/ou cloretadas na Zona de Afloramento com a unidade Hidroestratigráfica Santa Maria, fossilífera. Estudos recentes no noroeste do estado apontam uma associação com águas mais salinas, localmente termais, nas zonas confinadas, associando a origem do flúor às formações Pré-SAG, portadoras de sais e/ou minerais sulfatados. A hipótese mais consensual sugere a existência de misturas com águas salinas profundas, indicando existirem zonas onde predominam os fluxos verticais em relação aos horizontais no SAG, associadas à diques e a possivelmente a Capacidade de Troca Iônica dos argilominerais em um processo geogênico, de origem natural

Elemental analysis of wines from South America and their classification according to country

Elementos majoritários, minoritários e traço em vinhos provenientes de países produtores na América do Sul (Argentina, Brasil, Chile e Uruguai) foram determinados. A espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES) e a espectrometria de massa com plasma indutivamente acoplado (ICP-MS) em conjunto com nebulização pneumática e/ou nebulização ultra-sônica foram utilizadas. Foram determinados 45 elementos (Al, Ag, As, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Gd, Ho, K, La, Li, Lu, Mg, Mn, Mo, Na, Nd, Ni, P, Pb, Pr, Rb, Sb, Sn, Se, Sm, Sr, Tb, Ti, Tl, Tm, U, V, Yb e Zn) em 53 vinhos tintos. Mediante análise multivariada, os vinhos puderam ser discriminados de acordo com o país de origem, independentemente do tipo da uva. Os elementos discriminantes foram Tl, U, Li, Rb e Mg.Major, minor and trace elements in wines from wine-producing countries in South America (Argentina, Brazil, Chile, and Uruguay) were determined. Inductively coupled plasma optical emission spectrometry (ICP OES) and inductively coupled plasma mass spectrometry (ICP-MS) combined with pneumatic and/or ultrasonic nebulization were used. The concentrations of 45 elements (Al, Ag, As, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Gd, Ho, K, La, Li, Lu, Mg, Mn, Mo, Na, Nd, Ni, P, Pb, Pr, Rb, Sb, Sn, Se, Sm, Sr, Tb, Ti, Tl, Tm, U, V, Yb, and Zn) in 53 red wines were determined. By means of multivariate analysis, the wines could be discriminated according to the country of origin, regardless of the type of grape. The discriminant elements were Tl, U, Li, Rb, and Mg

Elemental analysis of wines from South America and their classification according to country

Elementos majoritários, minoritários e traço em vinhos provenientes de países produtores na América do Sul (Argentina, Brasil, Chile e Uruguai) foram determinados. A espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES) e a espectrometria de massa com plasma indutivamente acoplado (ICP-MS) em conjunto com nebulização pneumática e/ou nebulização ultra-sônica foram utilizadas. Foram determinados 45 elementos (Al, Ag, As, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Gd, Ho, K, La, Li, Lu, Mg, Mn, Mo, Na, Nd, Ni, P, Pb, Pr, Rb, Sb, Sn, Se, Sm, Sr, Tb, Ti, Tl, Tm, U, V, Yb e Zn) em 53 vinhos tintos. Mediante análise multivariada, os vinhos puderam ser discriminados de acordo com o país de origem, independentemente do tipo da uva. Os elementos discriminantes foram Tl, U, Li, Rb e Mg.Major, minor and trace elements in wines from wine-producing countries in South America (Argentina, Brazil, Chile, and Uruguay) were determined. Inductively coupled plasma optical emission spectrometry (ICP OES) and inductively coupled plasma mass spectrometry (ICP-MS) combined with pneumatic and/or ultrasonic nebulization were used. The concentrations of 45 elements (Al, Ag, As, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Gd, Ho, K, La, Li, Lu, Mg, Mn, Mo, Na, Nd, Ni, P, Pb, Pr, Rb, Sb, Sn, Se, Sm, Sr, Tb, Ti, Tl, Tm, U, V, Yb, and Zn) in 53 red wines were determined. By means of multivariate analysis, the wines could be discriminated according to the country of origin, regardless of the type of grape. The discriminant elements were Tl, U, Li, Rb, and Mg

Nutritional disorder in Pfaffia glomerata by mercury excess in nutrient solution

ABSTRACT:The mineral nutritional homeostasis in response to different concentrations of Hg (0, 25 and 50μM) was evaluated in Pfaffia glomerata plant. The exposure to the highest level of Hg (50µM) caused a decreasing in shoot and root fresh weights of 15.5% and 20%, respectively. Both shoot and root Hg concentrations increased linearly with increasing external Hg concentrations. Ca concentration decreased in shoot only at 50µM Hg, whereas shoot K and Mg concentrations decreased at both 25 and 50µM Hg, when compared to the control. A significant decrease in Cu, Zn, Fe and Mn concentrations in plants exposed to Hg was observed, but most Zn, Mn, and Cu in the roots. On the other hand, P concentration increased in both root and shoot of plants exposed at 25 and 50µM Hg, whereas Na concentration increased only in the root at 25 and 50µM Hg exposure. In general, tissue nutrient concentrations in P. glomerata plantlets exposed to Hg were significantly decreased, which indicates that the Hg may cause alteration on the mineral nutritional homeostasis of this species

Environmental quality evaluation of the Vacacaí River, Rio Grande do Sul, Brazil

The water quality of the Vacacaí River was assessed at different sites in the period between winter 2005 and autumn 2006. All samples were analyzed for 52 elements (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, Li, Be, Mg, Al, Ca, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, Ga, As, Se, Rb, Sr, Ag, Cd, In, Cs, Ba, Tl, Pb, Bi, U, Na, K, Hg, B, Mo, Sn, Te, Ti), temperature, pH, ammonia, and alkalinity levels. Water from the Vacacaí River ranged from slightly acidic to alkaline. No difference was observed in the chemical composition at different sites of the Vacacaí River. Levels of Ba, Ca, Sr and Mg increase in the dry seasons and reach their highest concentrations in autumn; Be and U decrease in the dry season and reach their highest concentration in spring. Al, Fe, Cr, Ni, Th, U Mn, Ca and Mg are highly positively related, indicating a common origin. Se and Cu are probably from anthropogenic source, from the rice crops of the margins of the river. Waterborne Al and Fe levels were above the desirable level for drinking water at all sites during all seasons. These results demonstrate the need for constant monitoring of water parameters, which is crucial to ensure water quality for the population of this region. © 2013 Springer-Verlag Berlin Heidelberg

Feasibility of Rare Earth Element Determination in Low Concentration in Crude Oil: Direct Sampling Electrothermal Vaporization-Inductively Coupled Plasma Mass Spectrometry

A comprehensive study was developed showing the feasibility of determination of rare earth elements (REE) in low concentration in crude oil by using direct sampling electrothermal vaporization system coupled to inductively coupled plasma mass spectrometry (ETV-ICP-MS). The effect of organic modifier on the REE signal was evaluated and the use of 6 mg of citric acid allowed calibration using aqueous reference solutions (selected pyrolysis and vaporization temperatures were 700 and 2200 °C, respectively). Because of the facility of REE in forming refractory compounds inside the graphite furnace during the heating step, the use of a modifier gas (Freon R-12, 3.0 mL min^–1) was necessary to allow quantitative vaporization of these elements. A flow rate of 0.40 L min^–1 was selected for both bypass and carrier gases. Under optimized conditions, the influence of sample mass was evaluated, and even using a relatively high mass of crude oil (up to 18 mg), accurate results were obtained. The accuracy was evaluated by the comparison of results by ETV-ICP-MS with those obtained by ICP-MS with ultrasonic nebulizer (USN) after high-pressure microwave-assisted wet digestion (MAWD) and microwave-induced combustion (MIC) and no statistical difference was observed between the results. The limits of quantification for REE by ETV-ICP-MS were lower (0.02–0.8 ng g^–1) than those obtained by USN-ICP-MS after MAWD and MIC (0.6–5.1 ng g^–1). Negligible blank values and relative standard deviations lower than 12% show the feasibility of the proposed ETV-ICP-MS method for routine analysis of crude oil