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Química Nova, Volume: 31, Número: 8, Publicado: 2008
  • Biomassa renovável e o futuro da indústria química Editorial

  • Parâmetros bioquímicos foliares das espécies Licania tomentosa (Benth.) e Bauhinia forficata (Link.) para avaliação da qualidade do ar Artigo

    Maioli, Otávio Luiz Gusso; Santos, Jane Meri; Reis Júnior, Neyval Costa; Cassini, Sérvio Túlio Alves

    Resumo em Inglês:

    Foliar analysis of biochemical parameters were carried out in order to investigate the influence of air pollutants on two tropical tree species (Licania tomentosa (Benth.) and Bauhinia forfícata (Link.)). Special attention was given to tropospheric ozone due to the fact that concentration levels in the region were found to be up to 140 µg m-3 for a 4 h average time, which is well above the value that can cause injuries to orchides and tobacco (59 µg m-3). Other pollutants such as nitrogen and sulphur oxides were measured and their ambient concentrations were also associated to biochemical alterations in the investigated species.
  • Artigo

    César, Isabela da Costa; Braga, Fernão Castro; Vianna-Soares, Cristina Duarte; Nunan, Elzíria de Aguiar; Pianetti, Gérson Antônio; Moreira-Campos, Ligia Maria

    Resumo em Inglês:

    This paper describes the development and validation of an UV-Visible spectrophotometric method for quantitation of genistein and genistin in soy dry extracts, after reaction with aluminum chloride. The method showed to be linear (r²= 0.9999), precise (R.S.D. < 2%), accurate (recovery of 101.56%) and robust. Seven samples of soy dry extracts were analyzed by the spectrophotometric validated method and by RP-HPLC. Genistein concentrations determined by spectrophotometry (0.63% - 16.05%) were slightly higher than values obtained by HPLC analysis (0.40% - 12.79%); however, the results of both methods showed a strong correlation.
  • Biossíntese de goma xantana a partir da fermentação de soro de leite: rendimento e viscosidade Artigo

    Nery, Tatiana Barreto Rocha; Brandão, Líllian Vasconcellos; Esperidião, Maria Cecília Azevedo; Druzian, Janice Izabel

    Resumo em Inglês:

    Xanthan is a polysaccharide synthesized by Xanthomonas bacteria and of extreme commercial importance as a microbial polysaccharide. The aim of this work was to produce xanthan using mozzarella cheese whey as substrate, by different isolates natives the Xanthomonas. The alternative medium for production was milk whey, urea and K2HPO4. The xanthan maximum productivity was 21.91 g L-1. Analysis of apparent viscosity was made in solutions of gum at 0.5-2.0%, 25-65 ºC with shear rate of 25-1000 s-1.The maximum viscosity found was 57.30 mPa.s. The isolates demonstrate capacity to degrade the lactose and to produce xanthan, being constituted an alternative for the industrial production.
  • Co-produção de lipase e biossurfactante em estado sólido para utilização em biorremediação de óleos vegetais e hidrocarbonetos Artigo

    Martins, Vilásia Guimarães; Kalil, Susana Juliano; Costa, Jorge Alberto Vieira

    Resumo em Inglês:

    Recently lipases have been increasing in prominence due to its wide industrial application. The lipase production can be influenced by different variables such as the producing microorganism, carbon sources, aeration and agitation conditions, inductor type and the geometry of the reactor. Biosurfactants are composites of surface active produced by microbial cells which reduce superficial and interfacial tensions. The objective of this study was to verify the influence of different process variables in the lipase production during a fermentative process. The results showed that the concomitant production of lipases and biosurfactant was possible in different cultivation conditions.
  • Elementos-traço e sódio em suco de uva: aspectos nutricionais e toxicológicos Artigo

    Assis, Roberta Amorim de; Küchler, Ivo Lewin; Miekeley, Norbert; Silveira, Carmem Lúcia Porto da

    Resumo em Inglês:

    Eight trace elements were determined in 20 Brazilian brands of grape juice, distributed over the country. Highest measured concentrations (As: 0.016; Cd: 0.010; Cr: 0.060; Cu: 1.28; Ni: 0.032; Pb: 0.016; Sb: 0.0040 and Zn: 1.44 mg L-1) comply with Brazilian maximal tolerance levels for inorganic contaminants (As: 0.5; Cd: 0.5; Cr: 0.1; Cu: 30; Ni: 3; Pb: 0.4; Sb: 1 and Zn: 25 mg L-1). Determination of arsenic species has shown inorganic As(V) as predominant in most samples. Sodium concentrations, nowadays a major public health concern, were also measured, showing an average of 149 mg L-1. Analytical results for this element were much higher than label concentrations, showing the need for better quality control.
  • Determinação de isotiocianato de benzila em Carica papaya utilizando cromatografia gasosa com detectores seletivos Artigo

    Castro, Izabela Miranda de; Anjos, Marianna Ramos dos; Oliveira, Elba dos Santos de

    Resumo em Inglês:

    In the present work, a method was developed and validated for the quantification of benzyl isothiocyanate (BITC) in the fruits of Carica papaya. The quantification of this compound was carried out by gas chromatography (GC) with selective detectors - nitrogen phosphorus detector (NPD) and flame photometric detector (FPD). The performance of these detectors showed a higher sensitivity of the NPD with a broader linear range of detection. The LOD/LOQ were 0.038/0.100 µg/mL for NPD and 5.78/19.29 µg/mL for FPD. The recovery of the method for BITC was 90,64%. An average value of BITC concentration in all the analyzed samples was 16,23 µg BITC/g.
  • Lipídios modificados obtidos a partir de gordura do leite, óleo de girassol e ésteres de fitosteróis para aplicação em spreads Artigo

    Ract, Juliana Neves Rodrigues; Gioielli, Luiz Antonio

    Resumo em Inglês:

    The objective of this paper was to evaluate the modifications in milkfat properties with the addition of sunflower oil (SO) and phytosterol esters (PE) and chemical interesterification. Fatty acid composition, softening point and consistency were determined. The saturation degree of milkfat decreased with the addition of SO and PE. Consequently, milkfat presented lower softening point and consistency. Chemical interesterification caused an increase in softening point due to the formation of higher amounts of trissaturated triacylglycerols with rearrangement. The incorporation of unsaturated fatty acids from SO and PE by milkfat triacylglycerols after chemical reaction caused linearization of consistency curves.
  • Micropartículas nanorrevestidas contendo um fármaco modelo hidrofóbico: preparação em etapa única e caracterização biofarmacêutica Artigo

    Domingues, Gislane Scholze; Guterres, Sílvia Stanisçuaski; Beck, Ruy Carlos Ruver; Pohlmann, Adriana Raffin

    Resumo em Inglês:

    The aim of this work was to prepare and characterize spray-dried nanocapsule-coated microparticles obtained in one step, using indomethacin as a hydrophobic drug model and poly(e-caprolactone) or Eudragit® RS100, as polymers. Nanocapsule-coated microparticles showed micrometric mean sizes (10 - 15 µm) and a reduced surface area (75 - 85 m²g-1) compared to the raw material (214 m²g-1). Microparticles coated with Eudragit® RS100-nanocapsules showed a better control of the drug release. The release profiles fit to the monoexponetial model and to the Power Law. The mechanism of the indomethacin release from the microparticles is non-Fickian and depends on the particles desagglomeration.
  • Aplicação da metodologia de superfície de resposta no estudo da produção e extração da poligalacturonase Artigo

    Santos, Sharline Florentino de Melo; Macedo, Gorete Ribeiro de; Silva, Flávio Luiz Honorato da; Souza, Rosane Liege Alves de; Pinto, Gustavo Adolfo Saavedra

    Resumo em Inglês:

    The aim of this work was to verify the effects of initial medium moisture content (U), addition of ammonium sulphate (N) and of potassium phosphate (P) in the production of the polygalacturonase through the solid-state fermentation, using cashew apple husk as substrate and Aspergillus niger CCT0916 as transformation agent. We also studied the best extraction conditions of the produced enzyme. The best condition of production was with U of 40%, 1% of N and 0% of P being reached an activity of the poligalacturonase of 10.1 U/g. The best extraction condition is an agitation system with a time of 100 min and a solvent-fermented medium volume ratio of 5 mL/g.
  • Constituintes químicos do caule de Senna reticulata Willd. (Leguminoseae): Chemical constituents isolated from the wood of Senna reticulata Willd. Artigo

    Santos, Rogério Nunes dos; Silva, Maria Goretti de Vasconcelos; Braz Filho, Raimundo

    Resumo em Inglês:

    The phytochemical investigation of the wood extracts of Senna reticulata (Leguminoseae) yielded six anthraquinones: chrysophanol, physcion, aloe-emodin, 1,3,8-trihydroxyanthraquinone, 3-methoxy-1,6,8-trihydroxyanthraquinone, emodin and the chrysophanol-10,10' bianthrone. The triterpenes a and b-amirin, the steroids b-sitosterol and stigmasterol as well as the flavonoid kaempferol were also identified. The structures were established by spectral analysis, including two-dimensional NMR techniques. It is the first report of 1,3,8-trihydroxyanthraquinone and 3-methoxy-1,6,8-trihydroxyanthraquinone in higher plants.
  • Estimativa de risco de contaminação das águas por pesticidas na região sul do estado do RS Artigo

    Cabrera, Liziara; Costa, Fabiane Pinho; Primel, Ednei Gilberto

    Resumo em Inglês:

    Pesticides can be quite useful in agricultural production, however, some pesticides after application can reach and contaminate the hydric resource. Pesticide monitoring must be careful because it is expensive and lengthy. Thus, in this work, a theoretical prediction was made using the approaches suggested by EPA-USA, the Groundwater Ubiquity Score index (GUS) and the Goss method associated with physicochemical properties of 27 pesticides used in a region in the south of Brazil. The results of this work led to the identification of the pesticides that should be prioritized in the environmental monitoring due to their high potential for contaminating water resources.
  • Constituintes químicos e avaliação do potencial antiinflamatório e antioxidante de extratos das folhas de Chomelia obtusa Cham. & Schltdl. (Rubiaceae) Artigo

    Barros, Michely Pereira de; Santin, Silvana Maria de Oliveira; Costa, Willian Ferreira da; Vidotti, Gentil José; Sarragiotto, Maria Helena; Souza, Maria Conceição de; Bersani-Amado, Ciomar Aparecida

    Resumo em Inglês:

    The phytochemical investigation of Chomelia obtusa leaves led to the isolation of four triterpenes (3-O-β-D-quinovopyranosyl-28-O-β-D-glycopyranosyl quinovic acid, 3-O-β-D-quinovopyranosyl-28-O-β-D-glycopyranosyl cincholic acid, and a mixture of ursolic and oleanolic acids), two flavonoids (3-O-β-D-glycopyranosyl quercetin, 3-O-[α-L-rhamnopyranosyl-(1→6)-β-D-galactopyranoside] quercetin), besides bornesitol and a mixture of 3,5- and 4,5-O-dicaffeoyl quinic acids. The structures of the isolated compounds were assigned on the basis of spectroscopic data, including two-dimensional NMR methods. The anti-inflammatory and antioxidant activities of the crude methanolic extract and of its fractions were evaluated. This is the first report on the chemical and biological investigation of the Chomelia genus.
  • Artigo

    Silva, Ana Carolina Conti e; Bastos, Deborah Helena Markowicz; Arêas, José Alfredo Gomes; Facanali, Roselaine; Marques, Marcia Ortiz M.

    Resumo em Inglês:

    The volatile compounds of raw and extruded bovine rumen, extracted by dynamic headspace, were separated by gas chromatography and analyzed by GC-MS. Raw and extruded materials presented thirty-two volatile compounds. The following compounds were identified in raw bovine rumen: heptane, 1-heptene, 4-methyl-2-pentanone, toluene, hexanal, ethyl butyrate, o-xylene, m-xylene, p-xylene, heptanal, limonene, nonanal, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane and octadecane. The following compounds were identified in the extruded material: 1-heptene, 2,4-dimethylhexane, toluene, limonene, undecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane and nonadecane. Mass spectra of some unidentified compounds indicated the presence of hydrocarbons with branched chains or cyclic structure.
  • Determinação da humificação da matéria orgânica de um latossolo e de suas frações organo-minerais Artigo

    Favoretto, Célia Mara; Gonçalves, Daniele; Milori, Débora M. B. P.; Rosa, Jadir Aparecido; Leite, Wellington Claiton; Brinatti, André Maurício; Saab, Sérgio da Costa

    Resumo em Inglês:

    Laser-induced fluorescence spectroscopy was used to determine the humification degree of the organic matter of a whole soil, that is, soil without any physical or chemical treatment. Particle size was determined in physically separated fractions. The humification of organic matter, the depth of the soil and the planting system can be correlated. On the surface of the soil, no tillage provided the smallest humification in comparison with the conventional tillage and reduced tillage. The fractions of the superficial layer of the soil (0-20 cm) indicated larger humification in the fraction from 20 to 53 µm and the smallest in the fraction of <2 µm.
  • Efeitos dos escoamentos urbanos e rurais na qualidade das águas do córrego verruga em vitória da conquista - Bahia, Brasil Artigo

    Santos, Maria Lúcia Pires dos; Santos, José Soares dos; Santos, Jarbas Rodrigues dos; Oliveira, Leandra Brito de

    Resumo em Inglês:

    This study examined the spatial and temporal variations of 13 physico-chemical parameters in water and sediment samples collected along the rural and urban section of Verruga Stream. The metal concentrations were determined by FAAS. The conductivity and the concentration of Na+, Cl-, and Ca2+ showed the largest variations in the urban area demonstrating that these parameters are appropriate indicators of urban contamination. The application of cluster and principal component analysis showed that the Cd2+ and Mn2+ are associated with the use of fertilizers in the rural area.
  • Síntese de poliestireno sulfonado para aplicações no tratamento de água produzido a partir de copos e bandejas descartadas de poliestireno Artigo

    Rodrigues Filho, Guimes; Assunção, Rosana M. N. de; Marques, Flavia C. A.; Corrente, Natália G.; Meireles, Carla da Silva; Cerqueira, Daniel A.; Landim, Alan S.

    Resumo em Inglês:

    In the present paper, the use of poly(styrene sulfonate) (PSS), produced from discarded polystyrene materials through heterogeneous and homogeneous processes, was investigated. The use of PSS for water treatment, using a kaolin suspension as wastewater model, reduced water turbidity for all the employed materials when compared to the blank analysis, without PSS. The most efficient polyelectrolyte was PSS cups obtained by homogeneous route. The same behavior was observed for real system. The homogeneous PSS cups showed a balance between a moderate molecular weight and high anionic character that improved flocks formation and water removal turbidity.
  • Artigo

    Martins, Leila Droprinchinski; Andrade, Maria de Fátima; Ynoue, Rita Yuri; Albuquerque, Édler Lins de; Tomaz, Edson; Vasconcellos, Pérola de Castro

    Resumo em Inglês:

    In order to characterize the composition of the main urban air organic compounds in the megacity of Sao Paulo, analysis of samples collected during the winter of 2003 downtown was carried out. The samplings were performed on the roof of a building in the commercial center of São Paulo. Hydrocarbons and carbonyls compounds were collected on August 4, 5 and 6. Comparing to previous data, the concentration of hydrocarbons presented no decrease in the concentration, except for the aldehydes, which decreased when compared to previous data. Among the HCs species analyzed, the highest concentrations observed were those of toluene (7.5 ± 3.4 ppbv), n-decane (3.2 ± 2.0 ppbv), benzene (2.7 ± 1.4 ppbv) and 1,3,5-trimethylbenzene (2.2 ± 1.5 ppbv).
  • Obtenção e caracterização de α-quitina e quitosanas de cascas de Macrobrachium rosembergii Artigo

    Battisti, Marcos Valério; Campana-Filho, Sergio P.

    Resumo em Inglês:

    The shells of Macrobrachium rosenbergii were submitted to deproteinization (Dp) and demineralization (Dm) aiming the extraction of α-chitin. The different parts of the shells were processed independently by carrying out sequence 1 (Dp/Dm) and sequence 2 (Dm/Dp). Both sequences allowed the extraction of chitins with low contents of calcium and magnesium, regardless of the part being processed. The sequence 1 lead to higher extraction yields while sequence 2 resulted in lower contents of inorganic compounds. Extensively deacetylated chitosans (GA<10%) of medium molecular weight (0,9 x 10(5) < Mv < 2 x 10(5) g/mol) resulted from the deacetylation of chitin.
  • Avaliação da composição química de sedimentos do Rio Barigüi na região metropolitana de Curitiba Artigo

    Froehner, Sandro; Martins, Raquel Fernandes

    Resumo em Inglês:

    Sediment samples from the Barigui River in Curitiba, south of Brazil, were evaluated following granulometric composition, organic carbon content, nitrogen, phosphorus and metals such as zinc, lead, chrome, nickel and cadmium. The sediments shown high percentage of phosphorus and nitrogen. Also the elemental organic C:N:P exceed the Redfield ratios possible because the large amount of sewage input into river. The presence of metals is also high, however the metal cadmium has not been found. But the other metals are in greater concentrations and possibly the presence of these metals is given by industrial and domestic sewage.
  • Amostragem do material particulado e fração orgânica volátil das emissões em motor ciclo diesel sem a utilização de túnel de diluição Artigo

    Menezes, Eliana Weber de; Cataluña, Renato

    Resumo em Inglês:

    Using a sampling method of particulate matter (PM) without the use of a dilution tunnel allows for evaluations of the volatile hydrocarbons (HC) in the emissions of diesel cycle engines. The procedure in this work applied a heated filter with temperature controlled. The volatile compounds are condensed at low temperature, allowing for evaluation of the HC by thermal desorption of the PM and for analysis of the condensed compounds of the exhaust gases.
  • Perda química de carbono e cinética do crescimento celular em cultivos de Spirulina Artigo

    Andrade, Michele da Rosa; Camerini, Felipe Vieira; Costa, Jorge Alberto Vieira

    Resumo em Inglês:

    Photosynthetic microorganism cultures, such as microalgae, represent one of the alternatives for fossil CO2 emissions mitigation. Carbon supply is the major cost component in microalgal cultures. Aiming to enhance the dissolved inorganic carbon uptake efficiency in microalgal cultures, Spirulina sp LEB-18 was cultivated in mediums containing NaHCO3 concentrations ranging from 2.8 to 100 g L-1. Results indicated that lower dissolved inorganic carbon concentratios (2.8 g L-1 NaHCO3) produce higher growth parameters (Xmax = 0.75 g L-1; Pmax = 0.145 g L-1 d-1; µmax = 0.254 d-1) and lower carbon losses (13.61%). At 50 g L-1 of NaHCO3 cell growth was inhibited and carbon losses reached 38.73%.
  • Determinação da relação siringila/guaiacila da lignina em madeiras de eucalipto por pirólise acoplada à cromatografia gasosa e espectrometria de massas (PI CG/EM) Artigo

    Barbosa, Luiz C. A.; Maltha, Célia R. A.; Silva, Vanessa Lopes; Colodette, Jorge Luiz

    Resumo em Inglês:

    The use of analytical pyrolysis combined with gas chromatography/mass spectrometry (Py-GC/MS) to determine the syringyl/guaiacyl ratio (S/G) in lignins from Eucalyptus spp woods was investigated. Sample of E. grandis and "E. urograndis" wood, with and without extractives, were subjected to pyrolysis from 300 ºC to 600 ºC. The products that results from pyrolysis were identified by mass spectrometry and the S/G ratio was determined based on the areas of the peaks corresponding to the guaiacyl and syringyl derivatives. The best S/G estimation is achieved when pyrolysis is carried out at 550 ºC. Extractives and carbohydrate present in the woods do not interfere with the results.
  • Investigação do potencial antioxidante e anticolinesterásico de Hippeastrum (Amaryllidaceae) Artigo

    Giordani, Raquel Brandt; Pagliosa, Letícia Balvedi; Henriques, Amélia T.; Zuanazzi, José Angelo S.; Dutilh, Julie H. A.

    Resumo em Inglês:

    Amaryllidaceae family is an important source of bioactive molecules and considering the taxonomic relationships, it is relevant to investigate the genus Hippeastrum. Thus, the aim of this work was to determine antioxidant and anticholinesterasic activities of Hippeastrum morelianum, Hippeastrum psittacinum and Hippeastrum santacatarina. Both antioxidant and acetylcholinesterasic activities of extracts were determinated by bioautography as 10 mg/mL and 0.1 mg/mL, respectively. The antioxidant activity of alkaloid lycorine, determinated spectrophotometrically with DPPH, indicated an IC50 value of 0.326 mM.
  • Artigo

    Narváez-Cuenca, Carlos Eduardo

    Resumo em Inglês:

    A technique for both extraction and activity measurement of peroxidase extracted from arazá (Eugenia stipitata Mc Vaugh) is described. Peroxidase from arazá pulp fruit was extracted using a combination of protein precipitation with acetone and extraction with 50 mM sodium buffer phosphate (pH 6.0). Optimum activity using guaiacol as H-donor was obtained at pH from 5.0 to 6.5, temperature from 60 to 75 °C, H2O2 between 10 to 15 mM and guaiacol from 80 to 160 mM. Thermal inactivation showed a first-order inactivation kinetic. Reactivation was observed when extracts were heated at 80 °C and afterwards incubated at 25 °C.
  • Alcalóides e outros metabólitos do caule e frutos de Zanthoxylum tingoassuiba A. St. Hil Artigo

    Silva, Cinara Vasconcelos da; Detoni, Cássia Britto; Velozo, Eudes da Silva; Guedes, Maria Lenise da Silva

    Resumo em Inglês:

    Phytochemical investigation of this species, popularly known as tinguaciba and used in traditional medicine to various diseases, resulted in the isolation of 15 substances: 2 alkaloids - norchelerythrine and arnottianamide; 1 lignan - sesamin; 4 terpenoids - citronellyl acetate, lupeol, α-bisabolol and spatulenol; 5 coumarins described for the first time - xanthotoxin, isopimpinelin, O-prenylumbelliferone, imperatorin and aurapten, 1 protoalkaloid - methyl N-methylanthranilate and 2 steroids - stigmasterol and β-sitosterol. The structures of the compounds were elucidated by spectroscopic analyses and compared with literature data.
  • Flavonóides, norisoprenóides e outros terpenos das folhas de Tapirira guianensis Artigo

    Correia, Suzimone de J.; DavidI, Jorge M.; Silva, Eliezer P. da; David, Juceni P.; Lopes, Lucia M. X.; Guedes, Maria Lenise S.

    Resumo em Inglês:

    From hexane fraction of methanol extract of leaves of Tapirira guianensis (Anacardiaceae) were obtained lupeol, 24-methylenecycloartan-3-ol, phytol, α-amyrin, β-amyrin, sitosterol, sitostenone, glycosyl sitosterol, as well as sitosterol esterified with palmitic and stearic acids. Phytol, α-amyrin and β-amyrin esterified with fatty acids were also identified from same extract. The EtOAc extract besides the norisoprenoids (6S,7E,9S)-6,9-dihydroxy-megastigma-4,7-dien -3-one 9-O-β-glucopyranoside and (6S,7E,9R)-6,9-dihydroxy-megastigma-4,7-dien-3-one 9-O-β-glucopyranoside also afforded kaempferol 3-O-rhamnoside, kaempferol 3-O-arabinofuranoside, quercetin 3-O-rhamnoside, and kaempferol. The structural elucidation of isolated compounds were based on UV, IR, MS, ¹H and 13C NMR data analysis.
  • Estudo cinético da decomposição térmica do pentaeretritol-tetranitrado (PETN) Artigo

    Silva, Gilson da; Nakamura, Nanci Miyeko; Iha, Koshun

    Resumo em Inglês:

    The pentaerythritol-tetranitrate (PETN) is a nitroether used in explosives and propellant formulations. Due to its suitable properties, PETN is used in booster manufacture. Knowing the thermal decomposition behavior of an energetic material is very important for storage and manipulation, and the purpose of this work is to study the kinetic parameters of the decomposition of PETN, compare the results with literature data and to study the decomposition activation energy differences between two crystalline forms of PETN (tetragonal and needle) by means of differential scanning calorimetry (DSC). Fourier transform infrared spectroscopy (FT-IR) is used to study the two crystalline forms.
  • Formação de micelas mistas entre o sal biliar colato de sódio e o surfactante aniônico dodecanoato de sódio Artigo

    Eising, Renato; Morés, Silvane; Bellettini, Ismael C.; Felippe, Arlindo C.; Dal-Bó, Alexandre G.; Zanette, Dino

    Resumo em Inglês:

    Mixed-micelle formation between sodium chlolate (NaC) and the anionic surfactant sodium dodecanoate (SDoD) in Tris-HCl buffer solutions, pH 9.00, varying the molar fraction of the surfactants, was investigated by means of electrical conductivity and steady-state fluorescence of pyrene. The critical micelar concentration (cmc) was measured from the equivalent conductance versus the square root of the molar surfactant concentration plots and the regular solution theory (RST) was used to predict the mixing behavior. The I1/I3 pyrene ratio-surfactant concentration plots were used as an additional technique to follow the behavior and the changes in the micropolarity of the mixed micelles.
  • Efeito do intemperismo artificial em quatro madeiras tropicais monitorado por espectroscopia de infravermelho (DRIFT) Artigo

    Pastore, Tereza Cristina Monteiro; Oliveira, Cynara Caroline Kern de; Rubim, Joel Camargo; Santos, Kelly de Oliveira

    Resumo em Inglês:

    Four tropical woods, were investigated to compare their performance and natural resistances to artificial weathering using the diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). The species were garapeira (Apuleia leiocarpa), itaúba (Mezilaurus itauba) and tauari (Couratari sp.), woods traditionally indicated for exterior uses, and marupá (Simarouba amara), that served as reference. The samples were submitted to cycles of UV radiation (350 nm) and water until 2,000 h. The photodegradation processes of woods surfaces were accomplished monitoring the changes in the intensities associated to lignin (1508 cm-1) and carbonyl group (1736 cm-1) absorptions. The results have shown that lignin was the first component to be photodegradated, resulting in surfaces mainly composed by cellulose, after 2,000 h of UV irradiation. The processes of formation and lixiviation of carbonyl compounds were different for each species. The experimental conditions used in this work were too severe to evaluate the wood density and extractives content influences during the treatment.
  • Artigo

    Valero, Manuel F.; Pulido, Jorge E.; Ramírez, Álvaro; Cheng, Zhengdong

    Resumo em Inglês:

    Castor oil was reacted by transesterification with various percentages in mass of pentaerythritol to obtain different esters of pentaerythritol. Alternatively, glycerol was also used instead of pentaerythritol for the same reaction in order to establish comparative reference products. The products of the reactions were characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy in order to detect and quantify (in terms of the molecular mass and structural information) the components of the products obtained. Analysis for hydroxyl value, acid value, viscosity and specific gravity were used to complete the characterization of the polyols obtained and also of the original castor oil. The polymer characterization was accomplished by tensile stress-strain tests, Shore A hardness, thermogravimetric analysis and chemical resistance to solvents.
  • Técnica de bombeio e prova para medidas de absorção de estado excitado e de emissão estimulada, em materiais sólidos dopados com íons terras raras Revisão

    Camargo, Andrea Simone Stucchi de; Nunes, Luiz Antonio de Oliveira

    Resumo em Inglês:

    Rare earth ion doped solid state materials are the most important active media of near-infrared and visible lasers and other photonic devices. In these ions, the occurrence of Excited State Absorptions (ESA), from long lived electronic levels, is commonplace. Since ESA can deeply affect the efficiencies of the rare earth emissions, evaluation of these transitions cross sections is of greatest importance in predicting the potential applications of a given material. In this paper a detailed description of the pump-probe technique for ESA measurements is presented, with a review of several examples of applications in Nd3+, Tm3+ and Er3+ doped materials.
  • Produção de biossurfactante por levedura Revisão

    Fontes, Gizele Cardoso; Amaral, Priscilla Filomena Fonseca; Coelho, Maria Alice Zarur

    Resumo em Inglês:

    Biosurfactants are molecules extracellularly produced by bacteria, yeast and fungi that have significant interfacial activity properties. This review focuses on relevant parameters that influence biosurfactant production by yeasts. Many works have investigated the optimization of yeast biosurfactant production, mainly within the last decade, revealing that the potential of such microorganisms is not well explored in the industrial field. The main points to increase the process viability lays on the reduction of the production costs and enhancement of biosynthesis efficiency through optimization the culture conditions (carbon and nitrogen source, pH, aeration, speed agitation) and the selection of inexpensive medium components.
  • A produção do conhecimento sobre o ensino de química nas reuniões anuais da Sociedade Brasileira de Química: uma revisão Revisão

    Francisco, Cristiane Andretta; Queiroz, Salete Linhares

    Resumo em Inglês:

    This paper discusses the Brazilian academic production on Chemical Education. The main source of information is the annual meeting of the Brazilian Chemical Society (RASBQ) covering the period 1999-2006. All the papers presented by the Division of Chemical Education of the RASBQ were reviewed to permit a discussion about the development of the area in Brazil. This bibliographical revision comprises the following aspects: year of presentation, Brazilian region and institution of production, scholastic level encompassed by the study, the kind of academic work (or research type) and thematic focus of the study.
  • HIV - recentes avanços na pesquisa de fármacos Revisão

    Cunico, Wilson; Gomes, Claudia R. B.; Vellasco Junior, Walcimar T.

    Resumo em Inglês:

    The development of new antiretroviral drugs is a dynamic process that is continuously fueled by identification of new molecular targets and new compounds for know targets. The current available drugs can be classified into five categories: nucleoside analogues reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, protease inhibitors, integrase inhibitors and entry inhibitors (fusion inhibitors and CCR5 antagonist). In addition, the maturation inhibitors may be considered as potential target for chemotherapeutic intervention. This review presents some anti-HIV agents that have already gone through the advance development process for final approval for the treatment of AIDS.
  • Cutinases fúngicas: propriedades e aplicações industriais Revisão

    Pio, Tatiana Fontes; Fraga, Laira Priscila; Macedo, Gabriela Alves; Kamimura, Eliana Setsuko

    Resumo em Inglês:

    Cutinases (EC 3.1.1.74) are also known as cutin hidrolases. These enzymes share catalytic properties of lipases and esterases, presenting a unique feature of being active regardless the presence of an oil-water interface, making them interesting as biocatalysts in several industrial processes involving hydrolysis, esterification and trans-esterification reactions. They are also active in different reaction media, allowing their applications in different areas such as food industry, cosmetics, fine chemicals, pesticide and insecticide degradation, treatment and laundry of fiber textiles and polymer chemistry. The present review describes the characteristics, potential applications and new perspectives for these enzymes.
  • Eletroforese capilar acoplada à espectrometria de massas (CE-MS): vinte anos de desenvolvimento Revisão

    Assunção, Nilson Antonio; Bechara, Etelvino José Henriques; Simionato, Ana Valéria Colnaghi; Tavares, Marina Franco Maggi; Carrilho, Emanuel

    Resumo em Inglês:

    CE-MS has been increasingly used for analysis of a vast array of compounds. This article reviews the different electrophoretic modes, interfaces and mass analyzers that are commonly used in the CE-MS coupling, as well as the technique advantages and performance characteristics. A large compilation of CE-MS applications is also presented. Therefore, this review is both a guide for beginners and a collection of key references for people who are familiar to the technique. Furthermore, this is the first CE-MS review published in a Brazilian journal and marks the installation of the first two commercial CE-MS units in Sao Paulo State.
  • Quimiossensores cromogênicos e fluorogênicos para a detecção de analitos aniônicos Revisão

    Zimmermann-Dimer, Lizandra Maria; Machado, Vanderlei Gageiro

    Resumo em Inglês:

    The detection of anionic species is a field which is currently attracting increasing interest. Research is carried out not only to gain a better understanding of biological events that anions participate in, but also to ascertain the potential contribution of the anionic chemosensors to the qualitative and quantitative analysis of species of interest in the areas of industry, medicine, the environment, and chemistry. This review summarizes several aspects related to the main strategies used in anion sensing. Each strategy discussed is illustrated with its potential applications citing recent examples. The prospects for their use in several areas are also described.
  • Nota Técnica

    Pedriali, Carla Aparecida; Fernandes, Adjaci Uchoa; Bernusso, Leandra de Cássia; Polakiewicz, Bronislaw

    Resumo em Inglês:

    The purpose of this study was to synthesize a water-soluble derivative of rutin (compound 2) by introducing carboxylate groups on rutin's sugar moiety. The rutin derivative showed an almost 100-fold solubility increase in water. The antiradical capacity of compound 2 was evaluated using the luminol/AAPH system, and the derivative's activity was 1.5 times greater than that of Trolox®. Despite the derivative's high solubility in water (log P = -1.13), lipid peroxidation of brain homogenate membranes was very efficiently inhibited (inhibition values were only 19% lower than the inhibition values of rutin).
  • Validação de metodologia analítica por cromatografia líquida de alta eficiência para quantificação de bupivacaína (S75-R25) em nanoesferas de poli(lactídeo-co-glicolídeo) Nota Técnica

    Moraes, Carolina Morales; Paula, Eneida de; Rosa, André Henrique; Fraceto, Leonardo Fernandes

    Resumo em Inglês:

    Bupivacaine (S75-R25, NovaBupi®) is an amide type local anesthetic widely used. The present work consists of the development and validation of analytical methodology for evaluation of NovaBupi® content in the poly-lactide-co-glycolide nanospheres (PLGA-NS) by high performance liquid chromatography. The separation was made using the reversed-phase column LC-18, acetonitrile/phosphate buffer 85:15 v/v as mobile phase and detection at 220 nm. The results obtained show that the analytical methodology is accurate, reproducible, robust and linear over the concentration range 10-220.0 g/mL of NovaBupi®. The method was applied to determine the encapsulation efficiency and evaluate the release profile of NovaBupi®, showing good results.
  • Construção de câmara de luz ultravioleta para fotopolimerização de fases estacionárias monolíticas Nota Técnica

    Vaz, Fernando Antonio Simas; Oliveira, Marcone Augusto Leal de; Queiroz, Marco Polo Garcia de; Ribeiro, Sidney José Lima

    Resumo em Inglês:

    The assembly of a photochemical reactor with six fluorescent lamps, used for photopolymerizations is described. This chamber presents a mobile support, allowing the placement of samples at different heights and a safety lock that interrupts the radiation, if it is opened during operation. The mirrored internal walls avoid the dispersion and non-uniform distribution of light. There is no high heating because the own character of the used lamps. All parts could be purchased in commerce with less than U$ 150,00. This reactor was successfully used for monolithic stationary phase photopolymerization.
  • Extração líquido-líquido de urânio(VI) do colofanito de itataia (Santa Quitéria, Ceará) por extratantes orgânicos em presença de ácido fosfórico Nota Técnica

    Ribeiro, Valeria Aparecida Leitão; Afonso, Júlio Carlos; Wildhagen, Glória Regina da Silva; Cunha, José Waldemar Silva Dias da

    Resumo em Inglês:

    This work describes the liquid-liquid extraction of uranium after digestion of colofanite (a fluoroapatite) from Itataia with sulfuric acid. The experiments were run at room temperature in one stage. Among the solutions tested the highest distribution coefficient (D > 60) was found for 40%vol. DEHPA (di(2-ethyl-hexyl)phosphoric acid) + 20% vol. TOPO (trioctylphosphine oxide) in kerosene. Thorium in the raffinate was quantitatively extracted by TOPO (0.1% vol.) in cyclohexane. Uranium stripping and separation from iron was possible using 1.5 mol L-1 ammonium or sodium carbonate (room temperature, one stage). However, pH control is essential for a good separation.
  • Determinação de metil-etil-cetona em amostras de urina com amostragem por micro extração em fase sólida (MEFS) em headspace associada à cromatografia gasosa com detector de ionização de chama (CG-DIC) Nota Técnica

    Antunes, Marina Venzon; Linden, Rafael

    Resumo em Inglês:

    Methyl ethyl ketone (MEK) is a solvent commonly used in chemical, paint and shoe industry. The aim of this study was to develop and validate a method for urinary quantification of MEK, employing headspace solid phase micro extraction sampling (SPME) coupled to gas chromatography with flame ionization detection (GC-FID). The calibration curve (y=4.6851x-0.0011) presented good linearity with r²=0.9993. Accuracy (94-109%), intra-assay precision (4.07-5.91%) and inter-assay precision (3.03-5.62%) were acceptable. The quantification limit was 0.19 mg/L. This low cost method can be used routinely in the biological monitoring of occupational exposure to MEK, according to the requirements of the Brazilian legislation.
  • Determinação eletroquímica da capacidade antioxidante de sucos de frutas industrializados usando o CRAC assay Nota Técnica

    Ferreira, Rafael de Queiroz; Avaca, Luis Alberto

    Resumo em Inglês:

    Fruits juices are natural sources of several compounds that present antioxidant action. Together with the fruits, they contribute with almost 40% of the antioxidant capacity in a healthy diet avoiding and preventing diseases deriving from oxidative stress. The present study determined the antioxidant capacity of seven samples of industrialized fruits juices applying CRAC (Ceric Reducing/Antioxidant Capacity) assay, a new electrochemistry assay that evaluates, by means of chronoamperometric measurements, the ability of a sample in reducing species Ce4+ in acid media. At the end of the assay was obtained the following classification: cashew > guava > grape > mango > apple > orange > passion fruit.
  • Concepções e ações de formadores de professores de química sobre o estágio supervisionado: propostas brasileiras e portuguesas Educação

    Silva, Rejane Maria Ghisolfi da; Schnetzler, Roseli P.

    Resumo em Inglês:

    The purpose of this paper is to investigate lecturers'actions and conceptions about pre-service teaching practices in chemistry. In this sense, it takes into account several theoretical references concerned with teacher education, which support the qualitative analysis of 18 interviews, gathered with 14 brazilian and 4 portuguese lecturers. Results reveal that the pre-service teaching practices in chemistry have been performed far from a technical approach, showing a paradigmatic rupture and presenting another logic related with teacher education in chemistry, which have improved the comprehension of the teachers' real practices, since these have been shaped by complex and unprescribed factors.
  • Educação

    García-Ruiz, Miguel Á.; Valdez-Velazquez, Laura L.; Gómez-Sandoval, Zeferino

    Resumo em Inglês:

    For some years, Chemistry teachers have used scientific visualization software of molecular models in computing rooms and chemistry laboratories for educational purposes. However, its application in classrooms has been limited. This article describes the integration and use of computer programs for scientific molecular visualization in a traditional classroom. We consider that the improvement of technical aspects of their application and use (usability) has a direct effect on students' understanding of molecular structures (including students' extrinsic motivation), among other factors. Consequently, we developed a guide for the integration of hardware and software of molecular visualization for its use in the classroom.
  • Experimento didático sobre cromatografia gasosa: uma abordagem analítica e ambiental Educação

    Penteado, José Carlos P.; Magalhães, Dulce; Masini, Jorge C.

    Resumo em Inglês:

    This paper describes an experiment to teach the principles of gas chromatography exploring the boiling points and polarities to explain the elution order of a series of alcohols, benzene and n-propanone, as well as to teach the response factor concept and the internal standard addition method. Retention times and response factors are used for qualitative identification and quantitative analysis of a hypothetical contamination source in a simulated water sample. The internal standard n-propanol is further used for quantification of benzene and n-butanol in the water sample. This experiment has been taught in the instrumental analysis course offered to chemistry and oceanography students.
  • Eletrodo compósito à base de grafite-araldite®: aplicações didáticas Educação

    Calixto, Carolina Maria Fioramonti; Cervini, Priscila; Cavalheiro, Éder Tadeu Gomes

    Resumo em Inglês:

    A composite electrode prepared by mixing a commercial epoxy resin Araldite® and graphite powder is proposed to be used in didactic experiments. The electrode is prepared by the students and applied in simple experiments to demonstrate the effect of the composite composition on the conductivity and the voltammetric response of the resulting electrode, as well as the response in relation to the scan rate dependence on mass transport. The possibility of using the composite electrode in quantitative analysis is also demonstrated.
  • Construção de um espectrógrafo de projeção e sua utilização em demonstrações de espectroscopia óptica Educação

    Azevedo, Eduardo Ribeiro de; Nunes, Luiz Antônio de Oliveira

    Resumo em Inglês:

    This article describes a projection spectrograph for use in optical spectroscopy classrooms demonstrations. The apparatus is based on an overhead projector and permits the visualization of several phenomena such as, light dispersion by diffraction gratings, diffraction order, optical fluorescence, continuous and discrete optical emission spectra, and light absorption by liquids and solids. A historical survey about the optical spectroscopy development is also presented.
  • Um panorama da nanotecnologia no Brasil (e seus macro-desafios) Assuntos Gerais

    Fernandes, Maria Fernanda Marques; Filgueiras, Carlos A. L.

    Resumo em Inglês:

    The objectives of this essay are to describe the development of nanoscience and nanotechnology (N&N) in Brazil. The analysis shows that Brazilian research in N&N is considered satisfactory and, although under other denominations, dates from at least 20 years. Innovation is still less satisfactory and there are different points of views on the issue. However, there is already a tendency towards the promotion of innovation in nanotechnology in the country. Scientists and the industrial sector have been showing interest in partnerships and some scientific policies stimulate this articulation between academy and companies.
  • Alographia dos álkalis... de Frei Conceição Veloso: um manual de química industrial para produção da potassa no Brasil colonial Assuntos Gerais

    Luna, Fernando J.

    Resumo em Inglês:

    Potassium carbonate, or potash, was the most important industrial chemical of the 18th century. It was essential for producing glass, soap, saltpeter, dyes, several drugs, and also used for bleaching linens, paper, and sugar. We examine here a book in which Brazilian author José Mariano da Conceição Veloso gathered his translations into Portuguese of English and French articles, letters, patents, and pamphlets with instructions on how to prepare potash. We discuss especially his version of Richard Watson's essay entitled 'Of saline substances', and Veloso's own 'Flora Alographica', a description of the Brazilian plants that could be used to prepare potash.
  • Avaliação da pós-graduação da área de química na CAPES e a internacionalização das revistas da Sociedade Brasileira de Química: Journal of the Brazilian Chemical Society e Química Nova Assuntos Gerais

    Pinto, Angelo C.; Cunha, Andréa S.

    Resumo em Inglês:

    This paper discusses of the use of the Impact Factor in the evaluation of chemistry graduate courses by CAPES and the internationalization of the Journal of the Brazilian Chemical Society and Química Nova.
  • Assuntos Gerais

    Pinto, Angelo Cunha
  • Errata Assuntos Gerais

Sociedade Brasileira de Química Secretaria Executiva, Av. Prof. Lineu Prestes, 748 - bloco 3 - Superior, 05508-000 São Paulo SP - Brazil, C.P. 26.037 - 05599-970, Tel.: +55 11 3032.2299, Fax: +55 11 3814.3602 - São Paulo - SP - Brazil
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