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Química Nova, Volume: 35, Issue: 4, Published: 2012
  • 35ª Reunião anual da sociedade brasileira de química Editorial

    Andricopulo, Adriano D.
  • Evaluation of the biocompatibility of glass and glass ceramics of the SNCP (SiO2-Na2O-CaO-P2O5) system Artigo

    Mundstock, Karoline Bastos; Oliveira, Antonio Pedro Novaes de; Hotza, Dachamir; Rogero, Sizue Ota

    Abstract in English:

    This article reports research results related to bioactivity and cytotoxicity tests using neutral red uptake method for glass powders and bulk glass ceramics belonging to the SNCP (SiO2-Na2O-CaO-P2O5) system. The obtained materials showed bioactivity when immersed in SBF promoting the surface deposition of HAp. When analyzed as powders, cytotoxicity was evidenced in the processed materials but not when bulk samples were tested.
  • Chemistry colaboration networks in Brazil: a coauthorship study in quimica nova articles Artigo

    Souza, Cristina Gomes de; Barbastefano, Rafael Garcia; Lima, Leonardo Silva de

    Abstract in English:

    In this paper we built three co-authorship networks displaying the acquaintances between countries, universities and authors that have published papers in Quimica Nova from 1995 to 2008. Our research was conducted applying a bibliometric approach to 1782 papers and over 4200 authors. Centrality measures were used and the most significant actors of each network were pointed out. The results using the centrality metrics and the network structures indicated that Quimica Nova resembles a typical scientific community.
  • Thermo-catalytic cracking of the mixture of used frying oil - textile stamping sludge for the production of oil with low acidity index Artigo

    Botton, Vanderléia; Riva, Dilamara; Simionatto, Edesio Luiz; Wiggers, Vinicyus Rodolfo; Ender, Laércio; Meier, Henry França; Barros, António André Chivanga

    Abstract in English:

    In this work, cracking experiments were performed to carry out the thermal conversion of the mixture of used frying oil and textile stamping sludge in continuous reactor. The textile stamping sludge was used to catalyze the reaction of thermal cracking. The physical and chemical properties of the oil produced were analyzed. Among the results of this analysis the level of acidity in the range of 12 mg KOH/g stands out. Low levels of acidity as this particular mean better quality oil. In this regard it is important that further researches on processes of conversion of residual oil occur.
  • Cellulose hydrolysis by mesoestruturated NiO-MCM-41 and MoO3-MCM-41 catalysts Artigo

    Silva, Adriano Sant'Ana; Silva, Flávio Luiz Honorato da; Carvalho, Maria Wilma N. Cordeiro; Pereira, Kleberson Ricardo de Oliveira; Lima, Ezenildo Emanuel de

    Abstract in English:

    This study was carried out to synthesize, characterize and evaluate the application of mesoestruturated catalysts MCM-41, 5%MoO3-MCM-41 and 5%NiO-MCM-41 in the hydrolysis of microcrystalline cellulose. XRD results indicate that the phase of mesoporous MCM-41 was obtained and that the introduction of metal oxides did not affect this mesoporous phase. About the heterogeneous hydrolysis reaction, it was observed that the increase in temperature results in a higher concentration of glucose and the catalyst 5%MoO3-MCM-41 provides the highest concentrations of glucose.
  • Sinterability of powders of parent glassceramic belonging to the lzsa system treated by ion exchange Artigo

    Montedo, Oscar Rubem Klegues; Ronsani, Patrícia; Oliveira, Antonio Pedro Novaes de

    Abstract in English:

    Ion exchange method was employed by means of surface modification of the glass powders of LZSA (Li2O-ZrO2-SiO2-Al2O3) system submitted to a 70wt% NaNO3/30wt% NaSO4 bath salt followed by a heat treatment. Chemical analysis by X-ray fluorescence was used to evaluate the efficiency of ion exchange, while optical dilatometry was employed to evaluate sintering of compacts. Evaluation of the structure of sintered bodies was made by scanning electron microscopy. Substitution of Li+ ions by Na+ ions on the surface of powders during heat treatments of 450 and 600 ºC for 2-10 h promoted an increase in densification of the sintered bodies.
  • Synthesis, antimicrobial and cytotoxic activities of 5-benzylidene-2-[(pyridine-4-ylmethylene)hydrazono]-thiazolidin-4-one and 2-[(pyridine-4-ylmethylene) hydrazono]-thiazolidin-4-one derivatives

    Feitoza, Danniel Delmondes; Alves, Antônio José; Lima, José Gildo de; Araújo, Janete Magali; Aguiar, Jaciana Santos; Rodrigues, Maria do Desterro; Silva, Teresinha Gonçalves; Nascimento, Silene Carneiro do; Góes, Alexandre José da Silva

    Abstract in English:

    A new series of 5-benzylidene-2-[(pyridine-4-ylmethylene)hydrazono]-thiazolidin-4-ones 4a-l have been synthesized. These compounds were designed by a molecular hybridization approach. 2-[(Pyridine-4-ylmethylene)hydrazono]-thiazolidin-4-ones 3a-d were also obtained and used as intermediates to give the target compounds. The in vitro antimicrobial and cytotoxic activities were evaluated for both series. The intermediate 3b showed considerable antibiotic activity against B. subtilis and C. albicans. In the cytotoxic activity compounds 3b (IC50= 4.25 ± 0.36 µg/mL) and 4l (IC50= 1.38 ± 0.04 µg/mL) were effective for inhibition of human erythromyeloblastoid leukemia (K-562) and human lung carcinoma (NCI-H292) cell lines, respectively.
  • Copper electrodeposition on glassy carbon and highly oriented pyrolytic graphite substrates from perchlorate solutions

    García-Rodríguez, Diana Elizabeth; Mendoza-Huizar, Luis Humberto; Rios-Reyes, Clara Hilda; Alatorre-Ordaz, Martín Alejandro

    Abstract in English:

    In present work, we analyzed the copper electrodeposition onto GCE (System I) and HOPGE (System II) from perchlorate solutions. The current density transients obtained from system I and II were well described through a kinetic mechanism that involves four different contributions: (a) a Langmuir type adsorption process, b) an electron transfer from Cu2+→Cu+, (c) a 3D nucleation limited by a mass transfer reaction and (d) a proton reduction process. It was observed that the values of the nucleation rate, the number of active nucleation sites were increased with the overpotential and they are bigger onto GCE in comparison with HOPGE.
  • Chemical characterization of the gels produced by the diazotrophic bacteria Rhizobium tropici and Mesorhizobium sp. Artigo

    Monteiro, Nilson Kobori; Aranda-Selverio, Gabriel; Exposti, Diego Tadeu Degli; Silva, Maria de Lourdes Corradi da; Lemos, Eliana Gertrudes Macedo; Campanharo, João Carlos; Silveira, Joana Léa Meira

    Abstract in English:

    The exopolysaccharides with characteristics of gel produced by Rhizobium tropici (EPS RT) and Mesorhizobium sp (EPS MR) are acidic heteropolysaccharide composed mainly of glucose and galactose in a molar ratio of 4:1 and 5:1 respectively, with traces of mannose (~ 1%). Chemical analysis showed the presence of uronic acid, pyruvate and acetyl-substituents in the structures of both polymers. Experiments of gel permeation chromatography and polyacrylamide gel electrophoresis showed that EPS RT and EPS MR are homogeneous molecules with low grade of polydispersity. The EPS were characterized using spectroscopic techniques of FT-IR, ¹H and 13C-NMR.
  • Tropical pteridophytes species in association with arbuscular mycorrhizal fungi in arsenic-contaminated soil Artigo

    Schneider, Jerusa; Oliveira, Letúzia Maria de; Guilherme, Luiz Roberto Guimarães; Stürmer, Sidney Luiz; Soares, Cláudio Roberto Fonsêca Sousa

    Abstract in English:

    The symbiosis of plants with mycorrhizal fungi represents an alternative to be considered during the processes of revegetation and rehabilitation of arsenic-contaminated soil. The aim of this study was to evaluate under greenhouse conditions the effect of arsenic on the mycorrhizal association of two species of tropical fern (Thelypteris salzmannii and Dicranopteris flexuosa). T. salzmannii had higher rates of colonization and higher density of spores while D. flexuosa showed greater sensitivity to smaller concentrations of arsenic and association with mycorrhizal fungi. Our results indicate that screening and selection of mycorrhizal fungal isolates/species is possible and effective for phytoremediation of arsenic-contaminated soils.
  • Influence of drying on the yield and chemical composition of volatile compounds from roots of Piper piscatorum Trel. & Yunck. (Piperaceae) Artigo

    Pimentel, Flávio Araújo; Cardoso, Maria das Graças; Andrade, Milene Aparecida; Zacaroni, Lidiany Mendonça; Guimarães, Luiz Gustavo de Lima

    Abstract in English:

    In this study, we evaluated the yield and chemical composition of volatile compounds obtained from fresh, dried at 30 and 40 ºC respectively of Piper piscatorum, employing the technique of hydrodistillation. The volatile were chemically characterized by GC-MS and GC-FID. The main volatile compounds were selin-11-en-4-a-ol (57,63 ± 3,07%; 53,95 ± 1,56% and 56,20 ± 0,43%) and benzyl benzoate (15,40 ± 0,36%; 16,32 ± 0,85% and 15,04 ± 0,24%).The drying of the raw material reduced yield of volatile compounds, changing their chemical compositions.
  • Rheological and thermal characteristics of wheat gluten biopolymers plasticized with glycerol

    Ferreira, Shana Pires; Ruiz, Walter Augusto; Gaspar-Cunha, António

    Abstract in English:

    The objective this work was to obtain bioplastics from mixtures of wheat gluten and glycerol by two different processes and evaluate their respective rheological properties. The mixtures and their respective bioplastics were obtained through direct batch mixing under approximately adiabatic and isothermal conditions. The bioplastics showed high values for the storage (G') and loss (G") moduli, suggesting a stronger protein network formed in both processes. The temperature onset and the percentage of weight loss to be estimated were found to be near in both bioplastics. The bioplastics have demonstrated to be materials of interesting potential of use as biodegradable barrier materials.
  • Characterization and in vitro release of cyclosporine-A from poly(D,L-lactide-co-glycolide implants obtained by solvent/extraction evaporation

    Saliba, Juliana Barbosa; Silva-Cunha Junior, Armando da; Silva, Gisele Rodrigues da; Yoshida, Maria Irene; Mansur, Alexandra Ancelmo Piscitelli; Mansur, Herman Sander

    Abstract in English:

    Cyclosporine-A-loaded PLGA implants were developed intended for ocular route. Implants were prepared using solvent extraction/evaporation technique followed by casting of the cake into rods in a heated surface. XRD patterns showed that cyclosporine-A was completely incorporated into PLGA. FTIR and DSC results indicated alterations on drug molecular conformation aiming to reach the most stable thermodynamic conformation at polymer/drug interface. Implants provided controlled/sustained in vitro release of the drug. During the first 7 weeks, the drug release was controlled by the diffusion of the cyclosporine-A; and between 7-23 week period, the drug diffusion and degradation of PLGA controlled the drug release.
  • Treatment for purification water of biodiesel using electrofloculation

    Brito, Juliana Ferreira de; Ferreira, Laís de Oliveira; Silva, Joaquim Paulo da; Ramalho, Teodorico Castro

    Abstract in English:

    Biodiesel was created as a solution for a great economic and enviromental problem of petroleum, a resource with sustainable characteristics. But its production still needs optimization, because it uses a lot of water and generates a large volume of this residue, which appears improper to disposal without correct treatment. This work propose an economic, viable and efficient way to treat the Biodiesel purification water, not only aiming at a proper disposal, but the reuse as input in the process, generating a large industrial economy, and greater environmental progress. For both treatment uses the electrofloculation technique.
  • Kinetics of oxidation of biodiesel from soybean oil mixed with TBHQ: determination of storage time

    Borsato, Dionísio; Maia, Elaine Cristina R.; Dall'Antonia, Luiz Henrique; Silva, Hágata Cremasco da; Pereira, Jaqueline Laís

    Abstract in English:

    Synthetic antioxidants are an alternative to prevent or retard the degradation of biofuels made from vegetable oils. In this study, it was evaluated the oxidative stability of B100 soybean oil biodiesel, in the presence of tercbutylhydroquinone (TBHQ). The results showed that the induction period, that precedes the seeding process, was delayed in the presence of the antioxidant. Moreover, the obtained results suggest that the B100 biodiesel containing TBHQ can present a storage time at 25 ºC, three times longer than the estimated time for the pure B100.
  • Evaluation of pesticide adsorption in gas chromatographic injector and column

    Pinho, Gevany Paulino de; Silvério, Flaviano Oliveira; Neves, Antônio Augusto; Queiroz, Maria Eliana Lopes Ribeiro de

    Abstract in English:

    Components in complex matrices can cause variations in chromatographic response during analysis of pesticides by gas chromatography. These variations are related to the competition between analytes and matrix components for adsorption sites in the chromatographic system. The capacity of the pesticides chlorpyrifos and deltamethrin to be adsorbed in the injector and chromatographic column was evaluated by constructing three isotherms and changing the column heating rate to 10 and 30 ºC min-1. By using ANCOVA to compare the slope of calibration graphs, results showed that the higher the injector temperature (310 ºC) the lower the pesticide adsorption. Also, deltamethrin influenced the adsorption of chlorpyrifos on the column chromatographic.
  • In vitro trypanocidal evaluation of pinane derivatives from essential oils of ripe fruits from Schinus terebinthifolius Raddi (Anacardiaceae)

    Sartorelli, Patricia; Santana, Jefferson S.; Guadagnin, Rafael C.; Lago, João Henrique G.; Pinto, Érika G.; Tempone, André G.; Stefani, Hélio A.; Soares, Marisi G.; Silva, Adalberto M. da

    Abstract in English:

    Essential oils of ripe fruits from Schinus terebinthifolius (Anacardiaceae), obtained using a pilot extractor and a Clevenger apparatus were chemically characterized. Due the high amount of (-)- α-pinene in both oils, this monoterpene was tested against the protozoan parasite Trypanosoma cruzi, showing a moderate potential (IC50 63.56 µg/mL) when compared to benznidazole (IC50 43.14 µg/mL). Otherwise, (-)- α-pinene oxide did not showed anti-trypanosomal activity (IC50 > 400 µg/mL) while (-)-pinane showed an IC50 of 56.50 µg/mL. The obtained results indicated that the epoxydation of α-pinene results to the loss of the anti-parasitic activity while its hydrogenation product, contributed slightly to the increased activity.
  • Modification of the performance of WO3-ZrO2 catalysts by metal addition in hydrocarbon reactions

    Torres, Gerardo Carlos; Manuale, Debora Laura; Benítez, Viviana Mónica; Vera, Carlos Román; Yori, Juan Carlos

    Abstract in English:

    A study of the different hydrocarbon reactions over Ni doped WO3-ZrO2 catalysts was performed. Ni was found as NiO at low Ni concentration while at high Ni concentrations a small fraction was present as a metal. For both cases, Ni strongly modified total acidity and concentration of strong acid sites. In the cyclohexane dehydrogenation reaction, Ni addition promotes both benzene and methyl cyclopentane production. The hydroconversion activity (n-butane and n-octane) increases with the augment of total acidity produced by Ni. The selectivity to reaction products is modified according to the acid strength distribution changes produced by Ni addition.
  • Preparation of glasses and glass ceramics of heavy metal oxides containing silver: optical, structural and electrochemical properties

    Bregadiolli, Bruna A.; Souza, Ernesto R.; Sigoli, Fernando A.; Caiut, José. M. A.; Alencar, Mônica A. S.; Benedetti, Assis V.; Nalin, Marcelo

    Abstract in English:

    Silver containing heavy metal oxide glasses and glass ceramics of the system WO3-SbPO4-PbO-AgCl with different AgCl contents have been prepared and their thermal, structural and optical properties characterized. Glass ceramics containing metallic silver nanoparticles have been prepared by annealing glass samples at temperatures above the glass transition and analyzed by transmission electron microscopy and energy dispersive X-ray microanalysis. The presence of the metallic clusters has been also confirmed by the observation of a surface plasmon resonance band in the visible range. Cyclic voltammetric measurements indicated the presence of metallic silver into the glasses, even before to perform the thermal treatment.
  • Preparation of association compound between rhodium(II) citrate and β-cyclodextrin

    Burgos, Ana E.; Okio, Coco K. Y. A.; Sinisterra, Rubén D.

    Abstract in English:

    Inclusion compound of rhodium(II) citrate with β-cyclodextrin in a 1:1 molar ratio was prepared using freeze-drying method. X-ray diffactometry, thermal analysis (TG/DTG/DSC), infrared and ¹H-NMR with ¹H spin lattice relaxation (¹H T1) measurements and 13C techniques were used to characterize the system prepared. The results indicated the formation of inclusion or association compounds between rhodium(II) citrate and β-cyclodextrin.
  • Development of an optical redox chemical sensor for nitrite determination

    Rastegarzadeh, Saadat; Kalantaripour, Mehdi

    Abstract in English:

    An optical chemical sensor for the determination of nitrite based on incorporating methyltrioctylammonium chloride as an anionic exchanger on the triacetylcellulose polymer has been reported. The response of the sensor is based on the redox reaction between nitrite in aqueous solution and iodide adsorbed on sensing membrane using anion exchange phenomena. The sensing membrane reversibly responses to nitrite ion over the range of 6.52×10-6 - 8.70×10-5 mol L-1 with a detection limit of 6.05×10-7 mol L-1 (0.03 µg mL-1) and response time of 6 min. The relative standard deviation for eight replicate measurements of 8.70×10-6 and 4.34×10-5 mol L-1 of nitrite was 4.4 and 2.5 %, respectively. The sensor was successfully applied for determination of nitrite in food, saliva and water samples.
  • An antimicrobial alkaloid and other metabolites produced by Penicillium sp. An endophytic fungus isolated from Mauritia flexuosa L. f.

    Koolen, Hector Henrique Ferreira; Soares, Elzalina Ribeiro; Silva, Felipe Moura Araújo da; Almeida, Richardson Alves de; Souza, Afonso Duarte Leão de; Medeiros, Lívia Soman de; Rodrigues Filho, Edson; Souza, Antonia Queiroz Lima de

    Abstract in English:

    The alkaloid glandicoline B (1) and six other compounds: ergosterol (2), brassicasterol (3), ergosterol peroxide (4), cerevisterol (5), mannitol (6) and 1-O-α-D-glucopyranoside (7) were isolated from Penicillium sp. strain PBR.2.2.2, a fungus from Mauritia flexuosa roots. The structures of the isolated metabolites were established by spectral analysis. MeOH extract of the fungal mycelium at 500 µg mL-1 exhibited antimicrobial activity against Staphylococcus aureus and the compound 1 at 100 µg mL-1 was active against S. aureus, Micrococcus luteus and Escherichia coli. The relationship between the bioactive properties of the fungus PBR.2.2.2 and those achieved for glandicoline B, as well the potential of this substance as bactericide is discussed.
  • Development of technology for producing electrodes and membrane electrode assemblies (MEAs) by sieve printing method for use in high power PEMFC stacks Artigo

    Fernandes, Valéria Cristina; Cunha, Edgar Ferrari da; Bonifácio, Rafael Nogueira; Dresch, Mauro André; Doubek, Gustavo; Santiago, Elisabete Inacio; Linardi, Marcelo

    Abstract in English:

    Significant functions in the Proton Exchange Membrane Fuel Cells (PEMFCs) rely on Gas Diffusion Layers (GDLs), such as control the water balance in the membrane electrode assembly (MEA), allow suitable gas permeability and porosity, etc. Aware of the GDL importance in the cell performance and its great demand in scale-up projects, the fuel cell research group at Instituto de Pesquisas Energéticas e Nucleares (IPEN) has developed a Sieve Printing method (innovative in Brazil) as a strategic solution for producing GDL and electrodes used in high power PEMFC stacks. The method has shown to be adequate to fabricate low cost electrodes, GDLs of different dimensions and to produce any amount of MEAs for power stacks.
  • Nitro derivatives and other constituents of Aristolochia melastoma

    Nogueira, Cláudio R.; Lopes, Lucia M. X.

    Abstract in English:

    A phytochemical study of Aristolochia melastoma Manso has led to the isolation and identification of 20 known compounds, including aristolochic acids, sodium aristolochates, lignan, flavonoids, and nitro phenylethyl derivatives. Their structures were established by spectroscopic analysis. The presence of thalictricoside and secoisolariciresinol dimethyl ether diacetate is reported for the first time in the Aristolochiaceae family. In addition, the presence of nitro compounds in this species is significant.
  • Sickle cell disease: challenges and advances in drug discovery Revisão

    Santos, Jean Leandro dos; Chin, Chung Man

    Abstract in English:

    Sickle Cell Disease (SCD) is a disease characterized by a punctual mutation (GTG - GAG) in the sixth codon of the gamma globin gene leading to a substitution of glutamic acid by a valine in the β chain of hemoglobin. Despite the huge progress on the molecular knowledge of the disease in recent years, few therapeutic resources were developed. Currently, the treatment is mainly done with the anticancer agent hydroxyurea. This review summarizes current knowledge about possible targets and new approaches to the discovery new compounds to treat the symptoms of SCD.
  • Romp as a versatile method for the obtention of differentiated polymeric materials

    Carvalho Jr., Valdemiro P.; Ferraz, Camila P.; Sá, José Luiz S.; Lima-Neto, Benedito S.

    Abstract in English:

    Ring Opening Metathesis Polymerization (ROMP) of cyclic olefins is a powerful transition metal-catalyzed reaction for syntheses of polymers and copolymers. The key feature of this reaction is the [2+2]-cycloaddition mechanism, with retention of the olefinic unsaturation in the polymer chain and occurrence of living polymerization. With the development of metal-carbene type catalysts for this process, many addressed polymeric materials have been successfully prepared to be employed in several fields of the science and technology. This review summarizes recent examples of syntheses of polymers with amphiphilic features such as block, graft, brush or star copolymers; as well syntheses of biomaterials, dendronized architectures, photoactive polymers, cross-linked or self-healing materials, and polymers from renewed supplies.
  • Construction and application of a portable microcontrolled turbidimeter for the in situ determination of sulfate

    Santos, Vagner B. dos; Guerreiro, Thiago B.; Faria, Ronaldo C.; Fatibello-Filho, Orlando; Suarez, Willian T.

    Abstract in English:

    This study reports on the construction of a turbidimeter employing light emitting diodes as radiation source at a wavelength of 405 nm, a photodiode as detector, a temperature sensor and a microcontroller used for data acquisition and processing. The turbidimeter was applied to determine sulfate concentrations in natural water employing barium chloride as reagent. Potential interferences and recovery studies were performed and an interference of 3.5 % and a recovery between 97.8 and 108 % were estimated. The analytical performance of in situ turbidimeter for the determination of sulfate was evaluated and compared with two commercial spectrophotometers and a good agreement was obtained.
  • Development and validation of analytical method for determination of sulfasalazine in oral suspension: comparasion between spectroscopic and high performance liquid chromathography Nota Técnica

    Costa, Mayre Aparecida Borges da; Ricci-Júnior, Eduardo; Santos, Elisabete Pereira dos; Mansur, Claudia Regina Elias; Campos, Vânia Emerich Bucco de

    Abstract in English:

    Sulfasalazine is a prodrug used in the treatment of the Chron's disease and rheumatoid arthritis. Two analytical methods for analysis of sulfasalazine in oral suspension were validated using Spectrophotometric and HPLC. There is not any pharmacopoeic method to assay sulfasalazine in oral suspension. The methods are insurance and fast execution for the quality control. Both, suspension and tablets 500 mg (Azulfin®) had been analyzed by methods using UV/VIS and HPLC and the results were satisfactory.
  • Chlorophenols in tap water from wells and surface sources in Rio de Janeiro, Brazil: method validation and analysis

    Sartori, André Victor; Krauss, Thomas Manfred; Braga, Ana Maria Cheble Bahia; Yamazaki, Aida Gomes de Almeida; Oliveira, Rosália Maria de

    Abstract in English:

    Two analytical methods were validated for determination of trichlorophenols, tetrachlorophenols and pentachlorophenol in drinking water. Limits of quantification were at least ten times lower than maximum permissible levels set by the Brazilian legislation, which are 200 ng mL-1 for 2,4,6-trichlorophenol and 9 ng mL-1 for pentachlorophenol. Chlorophenol levels were determined in tap water collected in the Municipality of Rio de Janeiro. 2,4,6-Trichlorophenol residues were detected in 36% of the samples, varying from 0.008 to 0.238 ng mL-1. All other analytes were below the limit of quantification. The validated methods showed to be suitable for application in routine quality control.
  • Set-up of a method using LC-UV to assay mometasone furoate in pharmaceutical dosage forms

    Ourique, Aline Ferreira; Contri, Renata Vidor; Guterres, Silvia Stanisçuaski; Beck, Ruy Carlos Ruver; Pohlmann, Adriana Raffin; Melero, Ana; Schaefer, Ulrich F.

    Abstract in English:

    A reliable method using LC-UV to assay mometasone furoate (MF) in creams or nasal sprays using the same chromatographic conditions was set up. Methanol:water 80:20 (v/v) (1.0 mL min-1) was used as mobile phase. MF was detected at 248 nm and analyzed in a concentration range from 1.0 to 20.0 µg mL-1. The method provided acceptable theoretical plates, peak simmetry, peak tailing factor and peak resolution a short run (5 min). The method showed specificity, good linearity (r = 0.9999) and the quantification limit was 0.379 µg mL-1. Furthermore, the method was precise (RSD < 2.0%), accurate (recovery > 97%) and robust.
  • Development of a UV/Vis spectrophotometric method for analysis of total polyphenols from Caesalpinia peltophoroides Benth

    Bueno, Fernanda G.; Machareth, Maria A. D.; Panizzon, Gean P.; Lopes, Gisely C.; Mello, João C. P.; Leite-Mello, Eneri V. S.

    Abstract in English:

    Caesalpinia peltophoroides is a domesticated tree found in Brazil. It was necessary to develop an analytical method to determine the content of total polyphenols (TP) in this herbal drug. The pre-analytical method was standardized for analysis time, wavelength, and the best standard to use. The optimum conditions were: pyrogallol, 760 nm, and 30 min respectively. Under these conditions, validation by UV/Vis spectrophotometry proved to be reliable for TP of the crude extract and semipurified fractions from C. peltophoroides. Standardization is required for every herbal drug, and this method proved to be linear, precise, accurate, reproducible, robust, and easy to perform.
  • Development and validation of a novel stability indicating RP-UPLC method for simultaneous determination of nizatidine, methylparaben and propylparaben in oral liquid pharmaceutical formulation

    Kumar, Navneet; Vaghela, Bhupendrasinh; Reddy, P. Sunil; Sangeetha, D.

    Abstract in English:

    A selective and accurate stability-indicating gradient reverse phase ultra performance liquid chromatographic method has been developed and validated for the simultaneous determination of nizatidine, methylparaben and propylparaben in pharmaceutical oral liquid formulation. The separation was achieved on Acquity UPLC TM HSS T3 1.8 µm column by using mobile phase containing a gradient mixture of solvent A (0.02 Mol L-1 KH2PO4, pH 7.5) and B (60:40 v/v mixture of methanol and acetonitrile) at flow rate of 0.4 mL min-1. Drug product was exposed to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. The developed method was validated as per international ICH guidelines with respect to specificity, linearity, accuracy, precision and robustness.
  • Quality control in potentiometric determination of acid volatile sulfides (AVS) using standard addition Nota Técnica

    Fagnani, Enelton; Guimarães, José Roberto; Grassi, Marco Tadeu; Fadini, Pedro Sérgio

    Abstract in English:

    This paper presents a quality assurance and quality control protocol in order to ensure the reliability of analytical results for the determination of acid volatile sulfides in environmental samples by potentiometry. The monitoring of the ion selective sensor readings must be realized continually and particularly in this situation where the analyte is susceptible to transformation and volatilization. Potentiometry with the standard addition was presented as a rapid, accurate, precise, feasible as well as a low cost technique. Concentrations of the analyte in the range of 0.49 to 1.02 mg L-1 were tested with percentage recoveries varying from 89 to 113%.
  • Problematization of experimental activities in Chemistry further education: a study of teaching texts - part II Educação

    Gonçalves, Fábio Peres; Marques, Carlos Aberto

    Abstract in English:

    Through the analysis of articles with proposals for experimental activities and with current pedagogical, epistemological and environmental discussion on experimentation by Chemistry professors, this paper investigates ways of highlighting relevant methodological characteristics that can be incorporated in experiments. 102 articles from national periodicals were analysed, all of which suggested experiments for use in Chemistry higher education. Based on analysis of the suggestions for experiments it appears that of particular importance are: visions, such as those that explain a belief that experimentation incentivizes motivation and conceptual learning; awareness of observation influenced by empiricism; and "errors" of students, which enrich their knowledge.
  • Different perspectives on knowledge required in initial teacher training of Chemistry Educação

    Farias, Sidilene Aquino de; Ferreira, Luiz Henrique

    Abstract in English:

    This study investigated different understandings about the educational needs of a professor of Chemistry, related to "know" and "know-how". It was verified the convergence and divergence of perceptions of high school students from that point to literature and education legislation. The research was conducted in five states in northern Brazil. The results show the little dialogue between training institutions and secondary schools, since the different understandings about the training needs go in opposite directions.
  • Scientific language rhetoric: from the theoretical basis to the production of didactic material for undergraduate Chemistry teaching Educação

    Oliveira, Jane Raquel Silva de; Queiroz, Salete Linhares

    Abstract in English:

    This work is part of a study that focused on analyzing the contributions of didactic activities related to scientific language rhetoric characteristics aimed at developing students' abilities to identify such characteristics in chemistry scientific texts and critical reading of those texts. In this study, we present the theoretical basis adopted to determine the scientific discourse characteristics and for the production of the didactic material used in those activities. Latour, Coracini and Campanario studies on persuasive rhetorical strategies present in scientific articles aided the production of such material.
  • Addition of amines to naphthoquinone in water and solid phase Educação

    Martinez, Sabrina T.; Silva, Bárbara V.; Pinto, Angelo C.; Ferreira, Vitor F.; Silva, Fernando de Carvalho da

    Abstract in English:

    Considering all the aspects of the principles of green chemistry, we present herein the addition reactions of amines to 1,4-naphthoquinone in water as solvent and also in solid phase. These reactions resulted in very colorful products that were easily monitored by thin layer chromatography and consequently easy to separate. Therefore, they are interesting experiments for experimental organic chemistry in the classrooms or in the laboratories.
  • From aromas and perfumes, the market of the "smell" industry Assuntos Gerais

    Speziali, Marcelo Gomes

    Abstract in English:

    Several flavors and fragrances (F&F) companies hold the economic leadership in the market, although not always have also the leadership in patent applications. The ranking of technological production in the fragrance area still remains with industries while scientific knowledge is equally shared between industries and academia. Contextualizing Brazil in this scene, despite all scientific expertise gained over the years, brazilian technological park is still at the beginning of the production of technologies applied directly to the F&F industries. The dependence on foreign technologies is remarkable as indicated by the great trade deficit in this sector.
  • Profa. Dra. Judith Felcman - sua vida acadêmica e contribuição à ciência Assuntos Gerais

    Toma, Henrique E.
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