Search

Your search keyword '"Pozebon, Dirce"' showing total 261 results
Start Over Author "Pozebon, Dirce"
261 results on '"Pozebon, Dirce"'

5. Bioimaging Metallomics

Author

Dressler, Valderi Luiz, Müller, Edson Irineu, Pozebon, Dirce, COHEN, IRUN R., Series Editor, LAJTHA, ABEL, Series Editor, LAMBRIS, JOHN D., Series Editor, PAOLETTI, RODOLFO, Series Editor, REZAEI, NIMA, Series Editor, and Arruda, Marco Aurélio Zezzi, editor

Published
2018
Full Text
View/download PDF

7. Metallomics Imaging

Author

Dressler, Valderi Luiz, primary, Hiedrich, Graciela Μarini, additional, Neves, Vinicius Machado, additional, Müller, Eson Irineu, additional, and Pozebon, Dirce, additional

Published
2020
Full Text
View/download PDF

25. Determination of fluoride in coal using pyrohydrolysis for analyte separation

Author

Dressler Valderi L., Pozebon Dirce, Flores Éder L. M., Paniz José N. G., and Flores Érico M. M.

Subjects
coal, fluoride, pyrohydrolysis, ion electrode, vanadium pentoxide, catalyst, Chemistry, QD1-999
Abstract

A method for the determination of fluoride in coal using pyrohydrolysis for sample decomposition is proposed. An apparatus was constructed, and the influence of vanadium pentoxide (V2O5) as a catalyst for the pyrohydrolysis reaction was investigated. It was verified that V2O5 does not influence the release of fluoride from coal. Certified and non-certified samples were analysed using an ion selective electrode (ISE) for analyte detection. Precise (RSD < 7%) and accurate (recovery in accordance with certified values) results were obtained. The limit of quantification (LOQ) of the method was 5.0 mugF/g of sample, using 20 mg of sample and a final dilution to 10 mL. The sample frequency was 5 samples h-1.

Published
2003

26. Effects of La2O3 nanoparticles and bulk-La2O3 on the development of Pfaffia glomerata (Spreng.) Pedersen and respective nutrient element concentration.

Author

Neves, Vinicius Machado, Heidrich, Graciela Marini, da Costa, Camila Cavalheiro, Farias, Julia Gomes, Nicoloso, Fernando Teixeira, Pozebon, Dirce, and Dressler, Valderi Luiz

Subjects
LASER ablation inductively coupled plasma mass spectrometry, TRACE elements
Abstract

Nanoparticles (NPs) have been progressively applied in the last decades, which may impact the environment. Synthesis of pigments, growing, and nutrient element uptake by plants can also be affected by NPs. The influence of lanthanum oxide nanoparticles (La2O3 NPs) on growth, pigment synthesis, and nutrient element uptake by Pfaffia glomerata (Spreng.) Pedersen, a medicinal plant native in South America, was evaluated in the present study. P. glomerata plantlets were cultivated for 28 days in the absence (control) and presence of 100, 200, and 400 mg L−1 of La2O3 NPs or bulk-La2O3 (b-La2O3) at the same cultivation conditions. Root development, aerial part growth, and pigment concentration in plants were affected by b-La2O3 and La2O3 NPs, mainly by La2O3 NPs. In spite of alteration of nutrient element concentration observed for the 100 and 200 mg L−1 of La2O3 NPs or b-La2O3 treatments, Ca, Cu, Fe, K, La, Mg, Mn, Mo, P, S, and Zn determination in stems and leaves revealed drastically and similar decrease of these elements in plants cultivated in the presence of 400 mg L−1 of La2O3 NPs or b-La2O3. Element distribution (mapping) determined by using laser ablation inductively coupled plasma mass spectrometry in leaves of plants submitted to treatment with 400 mg L−1 of b-La2O3 or La2O3 NPs showed differences in the distribution of elements, indicating distinct effects of b-La2O3 and La2O3 NPs on P. glomerata. As such, this study demonstrated that La2O3 NPs may impact plant growth. However, more investigations are necessary for better understanding of the effect of La2O3 on plants, including a broader range of concentration. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

43. Sample preparation strategies for petroleum cokedigestion and further cerium and lanthanumdetermination by DSN-ICP-OES

Author

Souza, J. P., Kellermann, Katherine, Camargo, M. S., Pozebon, Dirce, and Pereira, Juliana Severo Fagundes

Subjects
Cério, Lantânio, Petróleo
Abstract

The determination of cerium and lanthanum in petroleum coke samples by inductively coupled plasmaoptical emission spectrometry coupled to a desolvating nebulizer system (DSN-ICP-OES) is proposed forthefirst time after studying the following sample preparation methods: microwave-assisted digestion(MW-AD) in medium and high pressure systems and microwave-induced combustion (MIC). MW-AD ina medium pressure system was not suitable for digestion of petroleum coke even when using a lowsample mass (up to 100 mg). Both MIC and MW-AD in a high pressure system were considered suitablefor petroleum coke digestion, but MIC was preferable in view of the possibility of using diluted acid(2.5 mol L 1HNO3) to digest 400 mg of sample and obtaining lower residual carbon content (RCC)values (below 0.1% instead of approximately 25% for MW-AD). The use of MW-AD required a dilutionstep (with a factor of four) to minimize the interference in analyte determination by DSN-ICP-OES.Accuracy was evaluated by comparing the results with those obtained by neutron activation analysis (anagreement of more than 94% was obtained) and also analyzing spiked samples (recoveries in the rangeof 88 to 102% were achieved).

Published
2018

44. A comparative study of sheathing devices to increase robustness in inductively coupled plasma optical emission spectrometry via a nitrogen flow

Author

Scheffler, Guilherme Luiz, Pozebon, Dirce, and Beauchemin, Diane

Subjects
Espectrometria de emissão ótica com plasma indutivamente acoplado, Nitrogênio
Abstract

Five different glass sheathing devices were used to introduce 20 mL min 1 N2 sheathing gas around the effluent from the spray chamber to see the effect of their dimensions on plasma robustness as measured using the Mg II 280.270 nm/Mg I 285.213 nm emission signal ratio in inductively coupled plasma (ICP) optical emission spectrometry (OES). A clear relationship between device dimensions and the plasma robustness profile along the ICP central channel was observed. With an aerosol inlet having an inner diameter of 1.0 cm in the sheathing device, mixing of N2 with the aerosol was minimised and the resulting sheath increased robustness, the higher thermal conductivity of N2 versus Ar likely improving energy transfer between the bulk plasma and the central channel. The configuration of the outlet is also important, as any bottleneck favours mixing of N2 with the aerosol, which in turn cools the plasma, thereby shifting the region of maximum robustness to higher above the load coil. Regardless of device dimensions, plasma robustness was always better with N2 sheathing gas. An increased ion-toatom emission signal ratio also resulted for other elements than Mg. The presence of N2 also seems to affect excitation mechanisms, such as charge transfer between NO+ and Cd or Ni, which appears to take place at higher observation height, after N2 has had enough time to diffuse into the central channel.

Published
2018

Catalog

Books, media, physical & digital resources
See catalog results