Avaliação do método das adições de analito para a determinação de sódio em álcool combustível por espestrometria de emissão atômica em chama

Oliveira, Adriana Paiva de; Okumura, Leonardo Luiz; Neto, José Anchieta Gomes; Moraes, Mercedes de

doi:10.1590/s0100-46702002000200024

Cited by 9 publications

(9 citation statements)

References 4 publications

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“…The use of CTAH instead of CTAB for inversion of the electroosmotic flow avoids the negative peak 13 associated to the bromide peak (from CTAB), which would reduce the sensitivity of chloride. 4,2004 each cation (b). The peaks for ammonium (1), potassium (2), sodium (3), calcium (4), and magnesium (5) were also identified.…”

Section: Resultsmentioning

confidence: 99%

“…For cations, 20 mmol L -1 HIS/lactic acid and 2.5 mmol L -1 18-crown-6-ether 14 solution was used. The crown-ether was added to delay the K + peak, otherwise superimposed to the NH 4 + peak. Two hydrated ethanol fuel samples (A and B) were purchased at different local fuel station in the city of São Paulo and were stored in glass bottles carefully cleaned with ultra pure water.…”

Section: Reagents and Samplesmentioning

confidence: 99%

“…The contamination of the ethanol fuel with metal ions such as copper, iron, and sodium and inorganic anions such as chloride and sulfate can affect engine performance, since salts and sediments that are formed can block the nozzles and induce corrosion in the vehicle components in contact with the fuel. 2 Almeida et al 3 and Oliveira et al 4 described methodologies for sodium determination in ethanol fuel using flame photometry. The determination of metals in ethanol fuel by electrothermal atomic absorption spectrometry [5][6][7] is well established and flame atomic absorption spectrometry can be used for same determinations after preconcentration.…”

Section: Introductionmentioning

confidence: 99%

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Determination of inorganic ions in ethanol fuel by capillary electrophoresis

Muñoz¹,

Richter²,

Jesus³

et al. 2004

J. Braz. Chem. Soc.

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O controle do conteúdo de íons inorgânicos em combustíveis veiculares tem uma importante função na manutenção do motor. Um método novo e versátil para análise rápida de íons em etanol é apresentado. Eletroforese capilar foi utilizada para quantificar cátions (sódio, potássio, cálcio, magnésio e amônio) e ânions (sulfato, cloreto e nitrato). A injeção direta da amostra no capilar apresentou falta de repetibilidade nos resultados. A evaporação prévia do etanol, seguida pela resuspensão do material residual, levou a resultados confiáveis. Os limites de detecção para os oito íons estiveram na faixa de 0,06 a 0,18 mg L -1 . Limites de detecção inferiores podem ser obtidos com o aumento do tempo de injeção e/ou da pressão de injeção.The control of the content of inorganic ions in vehicular fuels plays an important role in the engine maintenance. A novel and versatile methodology to carry out rapid analysis of ions in ethanol is presented. Capillary electrophoresis was used to quantify cations (sodium, potassium, calcium, magnesium, and ammonium) and anions (sulfate, chloride, and nitrate). The injection of the sample directly in the capillary shows some lack of repeatability of the results. The prior evaporation of the ethanol, followed by a re-suspension of the residual material, leads to reliable results. The detection limits of the eight ions range between 0.06 and 0.18 mg L -1. Lower detection limits could be attained by increasing the injection time and/or the injection pressure.

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Section: Resultsmentioning

confidence: 99%

Section: Reagents and Samplesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Determination of inorganic ions in ethanol fuel by capillary electrophoresis

Muñoz¹,

Richter²,

Jesus³

et al. 2004

J. Braz. Chem. Soc.

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“…The quantitative monitoring of metal elements in fuels (including gasoline, alcohol, and diesel) is important from an economic perspective in the fuel industry as well as in the areas of transport and environment. The presence of metalspecies (ions or organometallic compounds) in automotive fuels can cause engine corrosion, reduce performance, and contribute to environmental contamination [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

“…Electrothermalatomizers include graphite tubes, tungsten filaments, and quartz tubes (for atomization of hydrides), as well as metal or ceramic tubes. Flame atomic absorption spectrometry (FAAS) is mostly used for elemental analysis at higher concentration levels, of the order of mg L -1 [3][4][5]. Table 1 lists some of the published studies concerning the application of AAS for determination of metals in fuels.…”

Section: Introductionmentioning

confidence: 99%

Analytical Methodology for Determination of Trace Cu in Hydrated Alcohol Fuel

Lobo¹,

Pollo²,

Villafranca³

et al. 2013

Liquid, Gaseous and Solid Biofuels - Conversion Techniques

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Many private and μovernmental initiatives have been established worldwide to identiλy viable alternatives to petroleum derivatives [ , ].The μoals are to reduce dependence on imported enerμy λrom non-renewable sources, while mitiμatinμ environmental problems caused by petroleum products, and to develop national technoloμies in the alternative enerμy λield.Ethyl alcohol ethanol is considered to be a hiμhly viable alternative λuel. Its production λrom biomass means that it can provide a source oλ enerμy that is both clean and renewable. The inclusion oλ ethanol as a component oλ μasoline can help to reduce problems oλ pollution in many reμions, since it eliminates the needto use tetraethyl lead historically notorious as a hiμhly toxic trace component oλ the atmosphere in major cities as an anti-knock additive.The quantitative monitorinμ oλ metal elements in λuels includinμ μasoline, alcohol, and diesel is important λrom an economic perspective in the λuel industry as well as in the areas oλ transport and environment. The presence oλ metalspecies ions or orμanometallic compounds in automotive λuels can cause enμine corrosion, reduce perλormance, and contribute to environmental contamination [ -].The low concentrations oλ metals in λuels typically require the use oλ sensitive spectrometric analytical techniques λor the purposes oλ quality control. Atomic absorption spectrometry AAS can be applied λor the quantitative determination oλ many elements metals and semi-metals in a wide variety oλ media includinμ λuels, λoodstuλλs, and bioloμical, environmental, and μeo-loμical materials, amonμst others. The principle oλ the technique is based on measurement oλ the absorption oλ optical radiation, emitted λrom a source, by μround-state atoms in the μas phase. Atomization can be achieved usinμ a λlame, electrothermal heatinμ, or speciλic chemical

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Quantitative assay of copper, iron, nickel, and zinc in fuel ethanol samples by flame atomic absorption spectrometry

Oliveira

Balbo

Andrade

et al. 2008

Chem Technol Fuels Oils

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After several petroleum crises in the 70's and 80's successive increases in petroleum barrel prices stimulated worldwide research and development of alternative fuels relative to fossil fuels. In this context, fuel ethanol obtained from sugarcane has been successfully applied as an important automotive fuel used in large scale in Brazil, in the pure form or as an addictive for gasoline, thus contributing economic and environmental advantages.Due to its use as an alternative automotive fuel or raw material for the alcohol-chemical industry, the identification and control of organic and inorganic contaminants is necessary because of the possibility of engine corrosion effects or passivation of industrial catalyzers [1]. Several organic[1-4] and inorganic[5-13] contaminants have been studied in fuel ethanol by different instrumental methods. In this case, different sources of contamination can be cited, such as during the production stage (micronutrients and fermentation processes), and during transport and storage of this fuel in metallic containers. The analysis of metallic species in this kind of matrix is of special interest due to its potential for environmental pollution when emitted during the combustion process and its contribution to corrosion effects in motors. Nowadays, Brazilian official methods for analysis of metallic species consist of dosage of sodium[14], copper[15], and iron[16] by using photometric and spectrometric methodologies proposed by the Brazilian Association of Technical Norms (ABNT).According to the literature, the determination of metallic species in fuel ethanol has been carried out using mainly spectrometric [5-11] and voltammetric[12-13] methods.When trace analysis is necessary, the preconcentration of analyte species before the determination step is often required. Voltammetric methods employing an anodic stripping step and using mercury electrodes (film or drop) can provide a preconcentration of analyte at the surface electrode by application of a specific potential during a selected preconcentration time, allowing to detection limits from 10 -9 until 10 -8 mol L -1 for several metallic species [12,13]. However, this technique is limited to a small number of metallic species for direct analysis. Iron and Nickel, for example, require addition of specific chemical reagents and need other technique (adsorptive stripping) or specific chemically modified working electrodes. ____________________________________________________________________________________________________

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Avaliação do método das adições de analito para a determinação de sódio em álcool combustível por espestrometria de emissão atômica em chama

Cited by 9 publications

References 4 publications

Determination of inorganic ions in ethanol fuel by capillary electrophoresis

Determination of inorganic ions in ethanol fuel by capillary electrophoresis

Analytical Methodology for Determination of Trace Cu in Hydrated Alcohol Fuel

Quantitative assay of copper, iron, nickel, and zinc in fuel ethanol samples by flame atomic absorption spectrometry

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