Artigo Publicado em Periódico (Química): Recent submissions

Now showing items 21-40 of 835

Determination of N,N-dimethyltryptamine in Mimosa tenuiflora inner barks by matrix solid-phase dispersion procedure and GC–MS

Gaujac, Alain; Aquino, Adriano; Navickiene, Sandro; Andrade, Jailson Bittencourt de (2012)

N,N-dimethyltryptamine (DMT) is a potent hallucinogen found in beverages consumed in religion rituals and neo-shamanic practices over the world. Two of these religions, Santo Daime and União do Vegetal (UDV), are represented ...
Comparison of three different sample preparation procedures for the determination of traffic-related elements in airborne particulate matter collected on glass fiber filters

Castilho, Ivan N. B.; Welz, Bernhard; Andrade, Jailson Bittencourt de; Smichowski, Patricia; Shaltout, Abdallah A.; Colares, Lígia; Carasek, Eduardo (2012)

Three different procedures for sample preparation have been compared for the determination of Cu, Mo and Sb in airborne particulate matter (APM) collected on glass fiber filters using high-resolution continuum source ...
Selenite biotransformation during brewing. Evaluation by HPLC–ICP-MS

Martínez, Maria Sánchez; Silva, Erik Galvão Paranhos da; Corona, Teresa Pérez; Cámara, Carmen; Ferreira, Sergio Luis Costa; Madrid, Yolanda (2012)

Yeast (Saccharomyces cerevisiae) and lactic bacteria have shown their ability to accumulate and transform inorganic selenium into organo Se compounds. The objective of this work was to evaluate selenium biotransformation ...
Factorial and Doehlert designs in the optimization of a separation procedure using polyurethane foam as a solid phase extractant for platinum determination in ferrous matrices using inductively coupled plasma optical emission spectroscopy

Araújo, Neyla Margarida Lopo de; Ferreira, Sergio Luis Costa; Santos, Hilda Costa dos; Jesus, Djane Santiago de; Bezerra, Marcos de Almeida (Brasil, 2012)

A procedure for separation of platinum from ferrous matrices was developed using platinum sorption as chloride complexes on polyurethane foam, with subsequent determination by inductively coupled plasma optical emission ...
Ethanol steam reforming over rhodium and cobalt-based catalysts: Effect of the support

Moura, Jadson Santos; Souza, Marluce Oliveira da Guarda; Bellido, Jorge David Alguiar; Assaf, Elisabete Moreira; Opportus, Marcelo; Reyes, Patrício; Varela, Maria do Carmo Rangel Santos (2012)

The effect of support on the properties of rhodium and cobalt-based catalysts for ethanol steam reforming was studied in this work, by comparing the use of magnesia, alumina and Mg–Al oxide (obtained from hydrotalcite) as ...
Evaluation of thermal stability of quinones by thermal analysis techniques

Sousa, Eliane Teixeira; Silva, Mateus Melo da; Andrade, Sandro José de; Cardoso, Manuela Pedra; Silva, Luciana Almeida; Andrade, Jailson Bittencourt de (2012)

The thermal behavior of quinones, such as 1,4-benzoquinone; 1,2-naphthoquinone; 1,4-naphthoquinone; 9,10-phenanthraquinone and 9,10-anthraquinone, was evaluated by simultaneous thermogravimetry (TG) and differential scanning ...
Ultrasound-assisted synthesis of ethyl esters from soybean oil via homogeneous catalysis

Brito, Jeane Quelle Alves; Silva, Creuza S.; Almeida, Jorge Santos de; Korn, Maria das Graças Andrade; Korn, Mauro; Teixeira, Leonardo Sena Gomes (2012)

A transesterification reaction of esters from soybean oil with ethanol assisted by low-frequency ultrasound (20 kHz) was performed in the presence of a potassium hydroxide catalyst. The effects of the following variables ...
Photo-oxidation using UV radiation as a sample preparation procedure for the determination of copper in fruit juices by flame atomic absorption spectrometry

Brandão, Geovani Cardoso; Aureliano, Márcio de Oliveira; Sauthier, Maria Celeste da Silva; Santos, Walter Nei Lopes dos (Brasil, 2012)

The present work proposes the photo-oxidation using UV radiation/H2O2 as an alternative procedure for pretreatment of industrialized fruit juice samples for determination of copper by flame atomic absorption spectrometry ...
Pt–Re–Ge/Al2O3 catalysts for n-octane reforming: Influence of the order of addition of the metal precursors

Carvalho, Luciene Santos de; Conceição, Karla C. S.; Mazzieri, Vanina A.; Reyes, Patricio; Pieck, Carlos L.; Varela, Maria do Carmo Rangel Santos (2012)

Trimetallic Pt–Re–Ge supported catalysts for naphtha reforming were prepared by successive impregnation of suitable precursors on gamma alumina. The order of addition of these precursors was varied and its influence on the ...
Description of atmospheric conditions at the Pierre Auger Observatory using the Global Data Assimilation System (GDAS)

Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, Ivone Freire da Mota e; Allard, D.; Allekotte, I.; Allen, J.; Pepe, Iuri Muniz (2012)

Atmospheric conditions at the site of a cosmic ray observatory must be known for reconstructing observed extensive air showers. The Global Data Assimilation System (GDAS) is a global atmospheric model predicated on ...
An unusual caffeic acid derived bicyclic [2.2.2] octane lignan and other constituents from Cordia rufescens

Vale, Ademir Evangelista do; David, Jorge Mauricio; Santos, Edlene O. dos; David, Juceni Pereira de Lima; Silva, Lidercia C. R. C. e; Bahia, Marcus Vinicius; Brandão, Hugo N. (2012)

This work reports isolation of an unusual lignan with a bicyclic [2.2.2] octene skeleton, named rufescenolide (1), from stems of Cordia rufescens, along with β-sitosterol, stigmasterol, syringaldehyde, 3-β-O-d-glucopyran ...
Reforma catalítica do metano sobre 1,5%Ni/α-Al2O3 dopado com elementos metálicos diferentes

Neiva, L. S.; Costa, A. C. F. M.; Andrade, Heloysa Martins Carvalho; Gama, L. (Brasil, 2012)

O objetivo deste trabalho é desenvolver catalisadores de Ni suportados em α-Al2O3 dopada com os seguintes elementos metálicos: ferro, zinco, cério e zircônio. Os suportes catalíticos de α-Al2O3 dopada foram obtidos por ...
Determination of copper, iron, nickel and zinc in ethanol fuel by energy dispersive X-ray fluorescence after pre-concentration on chromatography paper

Teixeira, Leonardo Sena Gomes; Santos, Elenir Souza; Nunes, Luana Sena (2012)

This paper presents an alternative analytical method employing energy dispersive X-ray fluorescence (EDXRF) to determine copper, iron, nickel and zinc ions in ethanol fuel samples after a pre-concentration procedure. Our ...
Assessment of physical-chemical characteristics of water and sediments from a Brazilian Tropical Estuary: status and environmental implications

Korn, Maria das Graças Andrade; Onofre, Cássia R. E.; Pereira, Madson de G.; Andrade, Marta Valéria Almeida Santana de; Ornelas, Vanessa C.; Almeida, Raimunda A. N. de; Fontes, Maurício P. F.; Ribeiro, Joselito N. (Brasil, 2012)

The environmental quality of the Jacu´ıpe River’s estuary (very important in northeastern Brazil) was assessed during 2007 and 2008. In water, concentrations (mg L−1) of NO2 − (<0.004 to 0.016), NO3 − (0.01 to 0.33), ...
A search for anisotropy in the arrival directions of ultra high energy cosmic rays recorded at the Pierre Auger Observatory

Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, Ivone Freire da Mota e; Allard, D.; Allekotte, I.; Allen, J.; Pepe, Iuri Muniz (2012)

Observations of cosmic ray arrival directions made with the Pierre Auger Observatory have previously provided evidence of anisotropy at the 99% CL using the correlation of ultra high energy cosmic rays (UHECRs) with objects ...
O trabalho experimental no ensino de Química

Lôbo, Soraia Freaza (Brasil, 2012)

This article deals with conceptions of the experimental work in the Chemistry teaching, developed among teachers and students. The research was carried out using qualitative methodology, based on Gaston Bachelard's thoughts. ...
Estudo espectroscópico de compósito obtido da reação no estado sólido entre um complexo mononuclear de vanádio(IV) e caulinita

Rezende, Edivaltris I. P. de; Mangrich, Antonio S.; Mangoni, Ana P.; Scarpellini, Marciela; Casellato, Annelise; Fernández, Tatiana L. (Brasil, 2012)

The use of probes, such as paramagnetic species diluted in diamagnetic materials in EPR spectroscopy, and mathematical tools such, as the Kubelka-Munk function in DRUV-VIS spectroscopy are strategies in the analysis of ...
Application of Multivariate Analysis in Mid-Infrared Spectroscopy as a Tool for the Evaluation of Waste Frying Oil Blends

Hocevar, Luciano Sérgio; Soares, Vitória Regina Bispo; Oliveira, Fábio Santos de; Korn, Maria das Graças Andrade; Teixeira, Leonardo Sena Gomes (2012)

Mid-infrared spectroscopy, in association with multivariate chemometric techniques, was employed for pattern recognition and the determination of the composition of waste frying oils (WFO); data are presented in terms of ...
Particle emission from heavy-duty engine fuelled with blended diesel and biodiesel

Sousa, Eliane Teixeira; Martins, Leila Droprinchinski; Silva Júnior, Carlos Roberto da; Solci, Maria Cristina; Pinto, Jurandir Pereira; Souza, Davi Zacarias; Vasconcellos, Pérola de Castro; Guarieiro, Aline Lefol Nani; Guarieiro, Lílian Lefol Nani; Andrade, Jailson Bittencourt de (2012)

In this study, particulate matter (PM) were characterized from a place impacted by heavy-duty vehicles (Bus Station) fuelled with diesel/biodiesel fuel blend (B3) in the city of Londrina, Brazil. Sixteen priority polycyclic ...
Desenvolvimento de dispositivo caseiro para dessalinização de água salobra a partir de sementes de umbu (Spondias tuberosa Arruda Câmara)

Menezes, Joilma da Silva; Campos, Vânia Palmeira; Costa, Tadeu Antônio de Campos (2012)

The goal of this work was to develop a homemade device to desalinate brackish water, using biological material like seeds from different plant species of the semi arid regions. Umbu seeds (Spondias tuberosa Arruda Câmara) ...

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