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Current Issue vol. 26, No. 5, 2015, p. 831-1053

 

Flow Analysis

Flow analysis can be acknowledged as a Brazilian triumph. In fact, the "tupiniquim"2 contributions to the development of this technique have been outstanding, especially after the inception of flow injection analysis and the related techniques. In this context, the pioneer application of flow injection systems to large-scale analyses of waters and plants at CENA/USP3,4 and the relevant conceptual, methodological and applicative achievements in different Brazilian institutions5 can be highlighted. These aspects were recognized when the Journal of the Brazilian Chemical Society was launched: the flow analysts at CENA/USP were invited to collaborate with a scientific article in its first issue.6 As a Brazilian, this makes me particularly proud.
The expressive number of available flow-based analytical methods, scientific articles and monographs, academic disciplines, workshops and commercially available flow analysers demonstrates that flow analysis reached maturity.

(Read more at Editorial)


Cover Article
J. Braz. Chem. Soc. 2015, 26(5), 978-984

Facile Graphene Oxide Preparation by Microwave-Assisted Acid Method

Marcelo M. Viana; Meiriane C. F. S. Lima; Jerimiah C. Forsythe; Varun S. Gangoli; Minjung Cho; Yinhong Cheng; Glaura G. Silva; Michael S. Wong; Vinicius Caliman

How to cite this article

Microwave-assisted acid method was used to expand graphite from Bay. The expanded graphite obtained was sonicated in acid medium to prepare wrinkled 2Dfew-layered graphene oxide with 5 to 9 layers that showed good stability in water from pH 4 to 12. The global process is a fast and energy-saving method compared to other processes described in the literature. Details are presented in the Article Facile Graphene Oxide Preparation by Microwave-Assisted Acid Method by Marcelo M. Viana, Meiriane C. F. S. Lima, Jerimiah C. Forsythe, Varun S. Gangoli, Minjung Cho, Yinhong Cheng, Glaura G. Silva, Michael S. Wong and Vinicius Caliman on page 978.

http://dx.doi.org/10.5935/0103-5053.20150061

Published online: March 13, 2015
Editorial J. Braz. Chem. Soc. 2015, 26(5), 831

Flow Analysis

Elias A. G. Zagatto

How to cite this article

 

http://dx.doi.org/10.5935/0103-5053.20150093

Communication J. Braz. Chem. Soc. 2015, 26(5), 832-836

Solventless and Mild Procedure to Prepare Organotellurium(IV) Compounds under Microwave Irradiation

Cleverson Princival; Alcindo A. Dos Santos; João V. Comasseto

How to cite this article

 

p-Methoxyphenyltellurium trichloride reacts with alkynes in a short reaction time under microwave irradiation in the absence of solvents.

http://dx.doi.org/10.5935/0103-5053.20150059

Published online: March 10, 2015

Review J. Braz. Chem. Soc. 2015, 26(5), 837-850

Recent Syntheses of Frog Alkaloid Epibatidine

Ronaldo E. de Oliveira Filho; Alvaro T. Omori

How to cite this article

 

This review presents the recent syntheses of epibatidine since 2002, summarized by the method used to obtain the azabicyclic core.

http://dx.doi.org/10.5935/0103-5053.20150045

Published online: February 24, 2015
Articles J. Braz. Chem. Soc. 2015, 26(5), 851-859

Molecular Electronic Topology and Fragmentation Onset via Charge Partition Methods and Nuclear Fukui Functions: 1,1-Diamino-2,2-dinitroethylene

Tiago Giannerini; Itamar Borges Jr.

How to cite this article

 

Topological methods and response functions were used to investigate in detail the electronic (charge) properties of 1,1-diamino-2,2-dinitroethylene (FOX-7) including acid-base properties and onset of fragmentation.

http://dx.doi.org/10.5935/0103-5053.20150044

Published online: February 24, 2015

J. Braz. Chem. Soc. 2015, 26(5), 860-868

Chemical Differentiation of Domestic Sewage Sludge and Cattle Manure Stabilized by Microbioreators: Study by Pyrolysis Coupled to Gas Chromatography Coupled to Mass Spectroscopy

Paulo R. Dores-Silva; Maria D. Landgraf; Maria O. O. Rezende

How to cite this article

 

The earthworms act as microbioreactors leading to various several unit operations that conduce the stabilization of the recent organic matter, transforming it in a more refratory material.

Published online: February 27, 2015
J. Braz. Chem. Soc. 2015, 26(5), 869-879

Determination of Aldrin Purity Using a Combination of the Mass Balance Approach and Quantitative NMR

Janaína M. Rodrigues; Eliane C. P. Rego; Evelyn F. Guimarães; Marcus V. B. Sousa; Tânia M. Monteiro; Laura A. Neves; Fernando G. M. Violante; Renato R. R. Almeida; Maria C. B. Quaresma; Raquel Nogueira

How to cite this article

 

Aldrin mass fraction was determined by mass balance, after determination of impurity mass fractions by gas chromatography with flame ionization detection, gas chromatography-mass spectrometry, gas chromatography with electron capture detector (organics), Karl Fischer coulometric titration (water content), and inductively coupled plasma mass spectrometry (inorganics). The results were validated through the participation of the National Institute of Metrology, Quality and Technology in the key-comparison CCQM-K55.b organized by Organic Analysis Working Group/International Bureau of Weights and Measures.

http://dx.doi.org/10.5935/0103-5053.20150047

Published online: February 27, 2015
J. Braz. Chem. Soc. 2015, 26(5), 880-886

Extraction and Separation of Molybdenum by Using Homogeneous Liquid-Liquid Microextraction via Flotation Assistance

Mohammad Rezaee; Maryam Mozaffari; Hedayat Haddadi; Mohammad R. Pourjavid; Abolfazl Semnani

How to cite this article

 

Homogeneous liquid-liquid microextraction via flotation assistance was investigated for the extraction of molybdenum from water samples. The developed method was sensitive, reproducible and linear over a wide range.

http://dx.doi.org/10.5935/0103-5053.20150048

Published online: February 27, 2015
J. Braz. Chem. Soc. 2015, 26(5), 887-898

Optimization of an Electrolyte System for the Simultaneous Separation of Nelfinavir Mesylate and Two Impurities by Micellar Electrokinetic Chromatography

Carina A. Bastos; Cláudia R. B. Gomes; Marcus V. N. de Souza; Marcone A. L. de Oliveira

How to cite this article

 

A methodology for the determination of nelfinavir and its impurities was proposed using micellar electrokinetic chromatography (MEKC)-UV. The electrolyte was optimized using mixed-level factorial design. The robustness (using Youden's test) showed that the buffer concentration had the greatest effect in the separation factor.

http://dx.doi.org/10.5935/0103-5053.20150049

Published online: February 27, 2015

J. Braz. Chem. Soc. 2015, 26(5), 899-909

Kinetic Investigation of Thermal Formation Processes of SiOC Glasses Derived from C-Containing Hybrid Polymeric Networks

Naiara V. Godoy; Mariana G. Segatelli

How to cite this article

 

The activation energies (Ea) of the thermal degradation processes in C-rich and poor SiOC glasses, determinated by Ozawa method, allowed to identify two degradation steps for all samples with different complexities.

http://dx.doi.org/10.5935/0103-5053.20150050

Published online: February 27, 2015

J. Braz. Chem. Soc. 2015, 26(5), 910-915

Microwave-Assisted Heck Arylations of Non-Activated N-Acyl-3-pyrrolines with Arenediazonium Tetrafluoroborates

Fernanda G. Finelli; Marla N. Godoi; Carlos R. D. Correia

How to cite this article

 

Effective Heck arylations of non-activated N-acyl-3-pyrrolines with arenediazonium salts were accomplished applying microwave irradiation.

http://dx.doi.org/10.5935/0103-5053.20150051

Published online: March 3, 2015

J. Braz. Chem. Soc. 2015, 26(5), 916-923

Cellulose Sulfuric Acid as an Eco-Friendly Catalyst for Novel Synthesis of Pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-5-ones

Sobhi M. Gomha; Sayed M. Riyadh

How to cite this article

 

In the present work, novel procedure for synthesis of pyrido[2,3-d][1,2,4]triazolo[4,3-a] pyrimidin-5-ones has been reported by using cellulose sulfuric acid as biopolymeric solid support acid catalyst.

http://dx.doi.org/10.5935/0103-5053.20150052

Published online: March 6, 2015

J. Braz. Chem. Soc. 2015, 26(5), 924-938

Application of Carbon Composite Adsorbents Prepared from Coffee Waste and Clay for the Removal of Reactive Dyes from Aqueous Solutions

Davis C. dos Santos; Matthew A. Adebayo; Eder C. Lima; Simone F. P. Pereira; Renato Cataluña; Caroline Saucier; Pascal S. Thue; Fernando M. Machado

How to cite this article

 

Dye-contaminated effluent treated with carbon composite adsorbent. Left untreated effluent, right treated effluent.

http://dx.doi.org/10.5935/0103-5053.20150053

Published online: March 6, 2015

J. Braz. Chem. Soc. 2015, 26(5), 939-948

Electrochemical Oxidation of Landfill Leachate: Investigation of Operational Parameters and Kinetics Using Graphite-PVC Composite Electrode as Anode

Zainab H. Mussa; Mohamed R. Othman; Md P. Abdullah

How to cite this article

 

Raw leachate is a complicated sample with high chemical oxygen demand (COD) and color. Hence, a cheap, effective, and easy electrochemical oxidation technique is used in this study to reduce the concentration of pollutants in terms of COD and color.

http://dx.doi.org/10.5935/0103-5053.20150055

Published online: March 10, 2015
J. Braz. Chem. Soc. 2015, 26(5), 949-954

Determination of Boron Isotope Ratios in Tooth Enamel by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) After Matrix Separation by Ion Exchange Chromatography

Maoyong He; Zhangdong Jin; Chongguang Luo; Li Deng; Jun Xiao; Fei Zhang

How to cite this article

 

The 10B/11B ratio in the enamel of the healthy teeth and carious teeth fluctuated over a broad range, ranged from 0.2007 to 0.2574. And it has significant variation with respect to age and gender.

http://dx.doi.org/10.5935/0103-5053.20150056

Published online: March 10, 2015
J. Braz. Chem. Soc. 2015, 26(5), 955-962

Determination of Polycyclic Aromatic Hydrocarbons in Groundwater Samples by Gas Chromatography-Mass Spectrometry After Pre-Concentration Using Cloud-Point Extraction with Surfactant Derivatization

Sarah A. R. Soares; Cibele R. Costa; Rennan G. O. Araujo; Maria R. Zucchi; Joil J. Celino; Leonardo S. G. Teixeira

How to cite this article

 

A cloud-point extraction method using the surfactant (30)p-tert-octylphenol polyoxyethylene was proposed as the preceding step for the determination of polycyclic aromatic hydrocarbons by gas chromatography-mass spectrometry.

http://dx.doi.org/10.5935/0103-5053.20150057

Published online: March 10, 2015

J. Braz. Chem. Soc. 2015, 26(5), 963-969

Construction of a New Aluminum(III) Cation Selective Electrode Based on 12-Crown-4 as an Ionophore

Masoomeh Esmaelpourfarkhani; Gholam H. Rounaghi; Mohammad H. Arbab-Zavar

How to cite this article

 

The macrocyclic ligand, 12-crown-4, was used as an ionophore for fabrication of a polyvinyl chloride based membrane sensor for aluminum(III) cation. It was successfully used for the determination of this metal cation in some rocks and aluminum-magnesium syrup.

http://dx.doi.org/10.5935/0103-5053.20150058

Published online: March 10, 2015
J. Braz. Chem. Soc. 2015, 26(5), 970-977

Intercalated 4-Aminobenzenethiol between Au and Ag Nanoparticles: Effects of Concentration and Nanoparticles Neighborhood on its SERS Response

Elias de Barros Santos; Fernando Aparecido Sigoli; Italo Odone Mazali

How to cite this article

 

Intercalated 4-aminobenzenethiol between gold and silver nanoparticles was prepared and its surface-enhanced Raman scattering (SERS) signal is dependent on sandwiched nanostructure.

http://dx.doi.org/10.5935/0103-5053.20150060

Published online: March 13, 2015

J. Braz. Chem. Soc. 2015, 26(5), 978-984

Facile Graphene Oxide Preparation by Microwave-Assisted Acid Method

Marcelo M. Viana; Meiriane C. F. S. Lima; Jerimiah C. Forsythe; Varun S. Gangoli; Minjung Cho; Yinhong Cheng; Glaura G. Silva; Michael S. Wong; Vinicius Caliman

How to cite this article

 

Expansion, exfoliation and oxidation of graphite using a microwave-assisted acid method to prepare few layers graphene oxide (GO) and reduced graphene oxide (rGO) film with relatively high electrical conductivity.

http://dx.doi.org/10.5935/0103-5053.20150061

Published online: March 13, 2015
J. Braz. Chem. Soc. 2015, 26(5), 985-991

Noteworthy Method for Direct Determination of SbIII and Total Inorganic Antimony in Natural Waters

Thaís S. Neri; Dayene C. Carvalho; Vanessa N. Alves; Nívia M. M. Coelho

How to cite this article

 

A procedure was developed for the direct determination of SbIII and total inorganic Sb in water samples by hydride generation atomic absorption spectrometry (HG AAS), without pre-reduction of SbV.

http://dx.doi.org/10.5935/0103-5053.20150062

Published online: March 17, 2015
J. Braz. Chem. Soc. 2015, 26(5), 992-1003

New Flexible and Transparent Solution-Based Germanium-Sulfide Polymeric Materials

Denise T. B. De Salvi; Aldo E. Job; Sidney J. L. Ribeiro

How to cite this article

 

These polymers present germanium and sulfur in their structure. They are transparent in the visible range and show flexibility. Other characteristic is the glass transition temperature found in temperatures below 0 °C, which may suggest applications in low temperatures.

http://dx.doi.org/10.5935/0103-5053.20150065

Published online: March 20, 2015
J. Braz. Chem. Soc. 2015, 26(5), 1004-1012

Silver Nanoparticle Thin Films Deposited on Glass Surface Using an Ionic Silsesquioxane as Stabilizer and as Crosslinking Agent

Andressa C. Schneid; Marcelo B. Pereira; Flavio Horowitz; Raquel S. Mauler; Carla R. Matte; Manuela P. Klein; Plinho F. Hertz; Tania M. H. Costa; Eliana W. de Menezes; Edilson V. Benvenutti

How to cite this article

 

One step deposition of thin films containing silver nanoparticles on glass surfaces was made using charged silsesquioxane as nanoparticle stabilizer and as crosslinking agent. The system showed antimicrobial activity and it is promising as coating for glass used as food package and for hospital instruments that require sterilization.

http://dx.doi.org/10.5935/0103-5053.20150066

Published online: March 20, 2015
J. Braz. Chem. Soc. 2015, 26(5), 1013-1027

On the Search for Potential Antimycobacterial Drugs: Synthesis of Naphthoquinoidal, Phenazinic and 1,2,3-Triazolic Compounds and Evaluation Against Mycobacterium tuberculosis

Guilherme A. M. Jardim; Eduardo H. G. Cruz; Wagner O. Valença; Jarbas M. Resende; Bernardo L. Rodrigues; Daniela F. Ramos; Ronaldo N. Oliveira; Pedro E. A. Silva; Eufrânio N. da Silva Júnior

How to cite this article

 

The present study describes the synthesis of naphthoquinoidal derivatives, phenazines and aryl triazoles as well as the evaluation of these compounds against Mycobacterium tuberculosis. This report represents an important contribution to the discovery of new anti-tuberculosis derivatives.

This article is part of the Special Issue Rare and Neglected Diseases - Vol. 25, No. 10 (2014).

http://dx.doi.org/10.5935/0103-5053.20150067

Published online: March 20, 2015

J. Braz. Chem. Soc. 2015, 26(5), 1028-1033

Theoretical Study of Molecular and Electronic Structures of 51 Knot Systems: Two-Layered ONIOM Calculations

Aguinaldo R. de Souza; Nelson H. Morgon

How to cite this article

 

Theoretical study of the molecular fragment present in the experimental structure of the [51 knot×××(PF6)9]Cl system using ONIOM(M06/6-31G(2d,p):PM6) method.

http://dx.doi.org/10.5935/0103-5053.20150068

Published online: March 20, 2015
J. Braz. Chem. Soc. 2015, 26(5), 1034-1042

Amperometric Detection of Isoprenaline Based on Glassy Carbon Electrode Modified by Iridium Oxide Nanoparticles

Mahmoud Roushani; Somayeh Farokhi

How to cite this article

 

A simple and very sensitive electrochemical sensor based on iridium oxide nanoparticles (IrOxNPs) has been developed by modification of glassy carbon electrode (GCE) and utilized to determine isoprenaline (IP). This sensor was used successfully for IP determination in human urine samples. The detection limit of the modified electrode toward IP was 90 nmol L-1.

http://dx.doi.org/10.5935/0103-5053.20150069

Published online: March 20, 2015
J. Braz. Chem. Soc. 2015, 26(5), 1043-1047

Biotransformation of the Diterpene Ent-18,19-dihydroxytrachylobane by Rhizopus stolonifer

Daniely H. P. Vasconcelos; Jair Mafezoli; Paula K. S. Uchôa; Natalia N. Saraiva; Mary A. S. Lima; José N. Silva Júnior; Francisco G. Barbosa; Marcos C. Mattos; Maria C. F. de Oliveira; Cristiano S. Lima; Maria N. G. Pessoa

How to cite this article

 

The diterpene ent-18,19-dihydroxytrachylobane was biotransformed by Rhizopus stolonifer, and yielded three new compounds: ent-11β,18,19-trihydroxytrachylobane, ent-16α,18,19-trihydroxykaur-11-ene and ent-18,19-dihydroxy-16α-methoxykaur-11-ene.

http://dx.doi.org/10.5935/0103-5053.20150070

Published online: March 20, 2015

Short Report J. Braz. Chem. Soc. 2015, 26(5), 1048-1053

Fluorescence Quenching of Two meso-Substituted Tetramethyl BODIPY Dyes by Fe(III) Cation

Lucas C. D. Rezende; Flavio S. Emery

How to cite this article

 

Chemical structures of the main borodiazaindacenes (BODIPYs) and the fluorescence turn-off observed under black light for the pyridyl-substituted BODIPY with growing concentration of Fe(III).

http://dx.doi.org/10.5935/0103-5053.20150054

Published online: March 6, 2015

Online version ISSN 1678-4790 Printed version ISSN 0103-5053
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