Voltammetric sensing of the fuel dye marker Solvent Blue 14 by screen-printed electrodes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A simple electroanalytical method for the analysis of the dye solvent orange 7 in fuel ethanol

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Analytical Methods Employed at Quality Control of Fuel Ethanol

The existence of organic and inorganic contaminants present in both fossil and biomass fuels and the fact that they can provide undesirable effects (environmental problems, corrosion processes, lead to storage instability, and others) implies a rigorous quality control of these fuels, although these contaminants make up a small part of the final fuel composition. Considering the rising importance of fuel ethanol in the worldwide panorama, this review aims at reporting the use of successful alternative analytical methods in the monitoring of organic and inorganic contaminants at trace levels, used to determine and to quantify these substances in fuel ethanol and also presenting all official norms for quality control of fuel ethanol employed by ABNT (Brazilian Association of Technical Norms), ASTM (American Society for Testing and Materials), and ECS (European Committee for Standardization).

Copper determination in ethanol fuel samples by anodic stripping voltammetry at a gold microelectrode

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Simultaneous determination of Cu and Pb in fuel ethanol by graphite furnace AAS using tungsten permanent modifier with co-injection of Ir

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Evaluation of Ir and Pd(NO3)(2)/Mg(NO3)(2) as Modifiers for the Simultaneous Determination of Mn, Ni, Pb, and Sb in Fuel Ethanol by Graphite Furnace MS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determination of Copper, Iron, Nickel and Zinc in fuel kerosene by FAAS after adsorption and pre-concentration on 2-aminothiazole-modified silica gel

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chemometrics in fuel science: demonstration of the feasibility of chemometrics analyses applied to physicochemical parameters to screen solvent tracers in Brazilian commercial gasoline

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Development, Optimization and Validation of Gas Chromatographic Fingerprinting of Brazilian Commercial Diesel Fuel for Quality Control

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Development and testing of anode-supported solid oxide fuel cells with slurry-coated electrolyte and cathode

A laboratory setup was designed and put into operation for the development of solid oxide fuel cells (SOFCs). The whole project consisted of the preparation of the component materials: anode, cathode and electrolyte, and the buildup of a hydrogen leaking-free sample chamber with platinum leads and current collectors for measuring the electrochemical properties of single SOFCs. Several anode-supported single SOFCs of the type (ZrO(2):Y(2)O(3)+NiO) thick anode/(ZrO(2):Y(2)O(3)) thin electrolyte/(La(0.65)Sr(0.35)MnO(3)+ZrO(2):Y(2)O(3)) thin cathode have been prepared and tested at 700 and 800 degrees C after in situ H(2) anode reduction. The main results show that the slurry-coating method resulted in single-cells with good reproducibility and reasonable performance, suggesting that this method can be considered for fabrication of SOFCs. (c) 2005 Elsevier B.V. All rights reserved.

Simultaneous determination of Al, As, Cu, Fe, Mn, and Ni in fuel ethanol by GFAAS

A method has been developed for the simultaneous determination of Al, As, Cu, Fe, Mn, and Ni in fuel ethanol by graphite furnace atomic absorption spectrometry (GFAAS) using a transversely heated graphite atomizer (THGA) with longitudinal Zeeman-effect background correction. The thermal behavior of analytes during the pyrolysis and atomization stages using the mixture Pd(NO3)(2) + Mg(NO3)(2) as the chemical modifier was investigated in 0.028 mol L-1 HNO3, 0.14 mol L-1 HNO3, and diluted ethanol (1 + 1, v/v) containing different nitric acid concentrations. With 5 rhog Pd + 3 mug Mg as the modifiers, pyrolysis and atomization temperatures of the heating program of the atomizer were fixed at 1200 C and 2200degreesC respectively. For 20 muL of diluted sample (10 muL ethanol + 10 muL of 0.28 mol L-1 HNO3) dispensed into the graphite tube, analytical curves in the 2.0 - 50 mug L-1 Al, As, Cu, Fe, Mn, Ni ranges were established. The calculated characteristic masses were - 37 pg Al, 73 pg As, 31 pg Cu, 16 pg Fe, 9 pg Mn, and 44 pg Ni, and the lifetime of the tube was around 2 50 firings. The limits of detection (LOD) based on integrated absorbance were 1.2 mug L-1 Al, 2.5 mug L-1 As. 0.22 mug L-1 Cu, 1.6 L-1 Fe 0.20 mug L-1 Mn 1.1 mug L-1 Ni. The relatively standard deviations (n = 12) were less than or equal to 3%, less than or equal to 6%, less than or equal to 2%, less than or equal to 3.4%, less than or equal to 1.3%, and less than or equal to 2% for Al, As, Cu, Fe, Mn, and Ni, respectively, the recoveries of Al, As, Cu, Fe, Mn and Ni added to fuel ethanol samples varied from 77% to 112%, 92% to 114%, 104% to 113%, 73% to 116%, 91% to 122% and 93% to 116%, respectively. Accuracy was checked for Al, As, Cu, Fe, Mn, and Ni determination in 20 samples purchased at local gas stations in Araraquara city, Brazil. A paired t-test showed that the results were in agreement at the 95% confidence level with those obtained by single-element GFAAS.

Simultaneous determination of zinc, copper, lead, and cadmium in fuel ethanol by anodic stripping voltammetry using a glassy carbon-mercury-film electrode

A new, versatile, and simple method for quantitative analysis of zinc, copper, lead, and cadmium in fuel ethanol by anodic stripping voltammetry is described. These metals can be quantified by direct dissolution of fuel ethanol in water and subsequent voltammetric measurement after the accumulation step. A maximum limit of 20% (v/v) ethanol in water solution was obtained for voltammetric measurements without loss of sensitivity for metal species. Chemical and operational optimum conditions were analyzed in this study; the values obtained were pH 2.9, a 4.7-mum thickness mercury film, a 1,000-rpm rotation frequency of the working electrode, and a 600-s pre-concentration time. Voltammetric measurements were obtained using linear scan (LSV), differential pulse (DPV), and square wave (SWV) modes and detection limits were in the range 10(-9)-10(-8) mol L-1 for these metal species. The proposed method was compared with a traditional analytical technique, flame atomic absorption spectrometry (FAAS), for quantification of these metal species in commercial fuel ethanol samples.

Refuse production in leaf-cutting ants (Hymenoptera: Formicidae) and its relationship with leaf harvest

We examined the relationship between fungal refuse production and vegetation input in a laboratory colony of the leaf-cutting ant Acromyrmex coronatus. We found only a strong 6-day time-delay in the production of refuse with variation in substrate intake.