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Química Nova, Volume: 33, Número: 1, Publicado: 2010
  • O que é sustentabilidade? Editorial

    Torresi, Susana I. Córdoba de; Pardini, Vera L.; Ferreira, Vitor F.
  • Desenvolvimento e aplicação de sistema passivo de coleta de poluentes atmosféricos para monitoramento de Cd, Cr, Pb, Cu, Fe, Mn, Zn e particulados totais Artigo

    Brait, Carlos Henrique Hoff; Antoniosi Filho, Nelson Roberto

    Resumo em Inglês:

    The objective of this study was to assess a new monitoring technique of particulate and trace metals in the atmosphere via the use of a passive sampler of air pollutants in the city of Goiânia. The average particulate weight and average concentrations of metals Fe, Cr, Zn, Pb, Cu, Mn, and Cd were 0.1104 g and 257.5; 23.4; 17.8; 6.7; 1.9; 0.8; 0.2 μg/m²/day, respectively. Higher Pb and Cr concentrations were obtained in areas with intense traffic. This study revealed that it is possible to monitor trace metals with passive sampling, developed at a low cost and operational facility.
  • Matéria orgânica em quatro tipos de solos brasileiros: composição química e sorção de atrazina Artigo

    Dick, Deborah Pinheiro; Martinazzo, Rosane; Knicker, Heike; Almeida, Paulo Sergio Gois

    Resumo em Inglês:

    Soil organic matter is the main sorptive soil compartment for atrazine in soils, followed in a minor scale by the inorganic fraction. In this study, the soil organic matter quality and atrazine sorption were investigated in four different soil types. The pedogenic environment affected the humification and therefore the chemical composition of the organic matter. The organic matter contribution to atrazine sorption was larger (60-83%) than that of the inorganic fraction. The organic matter capacity in retaining the herbicide was favoured by a higher decomposition degree and a smaller carboxylic substitution of the aliphatic chains.
  • Compostos bioativos do café: atividade antioxidante in vitro do café verde e torrado antes e após a descafeinação Artigo

    Lima, Adriene Ribeiro; Pereira, Rosemary Gualberto Fonseca Alvarenga; Abrahão, Sheila Andrade; Duarte, Stella Maris da Silveira; Paula, Fernanda Borges de Araújo

    Resumo em Inglês:

    This study aimed to evaluate the effect of coffee decaffeination with dichloromethane on the in vitro antioxidant activity of this matrix. It were determined the content of total phenolics, chlorogenic acid and caffeine of the coffee samples. The assessment of the antioxidant potential was investigated by DPPH radical scavenging method, reducer power and Fe2+chelation activity. The process of decaffeination and roasting caused changes in the levels of the compounds investigated. The results show that the decaffeination by the dichloromethane method reduces the in vitro antioxidant potential of coffee.
  • Retenção de metais pesados em micélio de fungos micorrízicos arbusculares Artigo

    Cabral, Lucélia; Siqueira, José Oswaldo; Soares, Claúdio Roberto Fonsêca Sousa; Pinto, José Eduardo Brasil Pereira

    Resumo em Inglês:

    This work evaluated the kinetics as well as the retention capacity of Cu, Zn, Cd, and Pb by arbuscular mycorrhizal fungi (AMF) mycelium. The metal retention is a fast process with Cu being retained 3, 30, and 60 times faster than Zn, Cd, and Pb, respectively. Metal retention capacity varied amongst the different tested AMF species and decreased in the following order: Cu>Zn>>Cd>Pb. The Glomus clarum mycelium showed the highest retention capacity for Cu, Cd and Pb, whereas Zn was mostly retained by Gigaspora gigantea mycelium. The simultaneous application of all tested metals in solution decreased Cu and Zn retention by AMF mycelium. The high retention capacity of Cu and Zn by mycelium of G. clarum and G. gigantea suggests a promising use of these isolates in phytoremediation.
  • Abietatrienes diterpenoids from Sagittaria montevidensis SSP Montevidensis

    Tanaka, Clara M. A.; Radke, Vanessa S. C. O.; Silva, Cleuza C. da; Nakamura, Celso V.; Oliveira, Pollyanna L. de; Kato, Lucilia; Oliveira, Cecília M. A. de

    Resumo em Inglês:

    The antimicrobial properties of the hexane, hexane/EtOAc and methanol fractions of the fresh petioles of Sagittaria montevidensis ssp montevidensis (Alismataceae) were evaluated against fungi and Gram-negative and Gram-positive bacteria. A new abietatriene-type diterpenoid, 3β,7α-dihydroxi-abieta-8,11,13-triene and the known 3β-hydroxy-abieta-8,11,13-trien-7-one were isolated from the most active fraction tested and the structures of these compounds were elucidated by data including IR, EIMS, and 1D and 2D NMR spectra.
  • Variações no teor e na composição volátil de Hyptis marrubioides EPL: cultivada no campo e em casa de vegetação Artigo

    Botrel, Priscila Pereira; Pinto, José Eduardo Brasil P.; Araújo, Ana Clara Caxito de; Bertolucci, Suzan Kelly Vilela; Figueiredo, Felipe Campos; Ferri, Pedro Henrique; Costa, Deomar Plácido da

    Resumo em Inglês:

    This work describes the chemical composition of the volatile oil of Hyptis marrubioides cultivated in field and greenhouse. The experimental design was completely randomized, with ten replications for each type of cultivation. The volatile oil was extracted by hydrodistillation and analyzed by GC-MS. The highest content of volatile oil was found for plants grown in field. The highest percentage of the compounds present in oils was observed in samples grown in the field, such as germacra-4(15),5,10(14)-trien-1-α-ol (16.34%), β-caryophyllene (10.42%), γ-muurolene (12.83%) and trans-thujone (9.98%). However, some compounds were found only in plants grown in a greenhouse, such as cis-muurol-5-en-4α-ol (10.84%), α-cadinol (3.06%) and eudesma-4(15),7-dien-1β-ol (6.82%).
  • Enriquecimento de compostos fenólicos de folhas de Inga edulis por extração em fase sólida: quantificação de seus compostos majoritários e avaliação da capacidade antioxidante Artigo

    Dias, Aécio Luís de Sousa; Souza, Jesus Nazareno Silva de; Rogez, Hervé

    Resumo em Inglês:

    A phenolic fraction was obtained from of the acetone-water-acetic acid extract of Inga edulis leaves, by liquid-liquid partition and SPE-C18 cartridges. This method provided an increase of 108, 66, 51, 50 and 36% of flavonols, proanthocyanidins, total polyphenols, gallotannins and flavanols, respectively. The major phenolics in purified fraction were procyanidin B2, catechin and myricetin-3-O-α-L-rhamnopyranoside, which achieved increases of 111, 47 and 45%, respectively, after SPE. Acid hydrolysis confirmed the presence of procyanidins, prodelphinidins and glycosylated flavonoids.
  • Photometric procedure for quantitative analysis of Aflatoxin B1 in peanuts by thin-layer chromatography using charge coupled device detector

    Hoeltz, Michele; Welke, Juliane Elisa; Noll, Isa Beatriz; Dottori, Horacio Alberto

    Resumo em Inglês:

    A photometric procedure was developed for determination of aflatoxin B1 in peanuts by TLC-CCD technique. The quantification and detection limit were 1.2 μg kg-1 and 0.4 ng per spot, respectively, with mean recovery of 98%. The CCD camera is sufficiently sensitive to detect small changes in spots fluorescence intensity and the results for performance confirmed the efficiency of the method. Another important property of CCD detector is its linearity for a wide range of luminous stimulus determined by analysis of five-point calibration curves using the intensity of AFB1 fluorescence versus AFB1 concentration (0.8 to 4.8 ng per spot). The method was applied to the analysis of thirty nine peanut samples and aflatoxin B1 levels ranged from 16 to 115 μg kg-1. The TLC-CCD and the photometric procedure developed in this study demonstrated to be a simple and efficient tool for quantitative analyses of AFB1 in peanut samples.
  • Low metal loading catalysts used for the selective hydrogenation of styrene

    Badano, Juan; Lederhos, Cecilia; Quiroga, Mónica; L'Argentière, Pablo; Coloma-Pascual, Fernando

    Resumo em Inglês:

    A series of Group VIII metal catalysts was obtained for the semi-hydrogenation of styrene. Catalysts were characterized by Hydrogen Chemisorption, TPR and XPS. Palladium, rhodium and platinum low metal loading prepared catalysts presented high activity and selectivity (ca. 98%) during the semi-hydrogenation of styrene, being palladium the most active catalyst. The ruthenium catalyst also presented high selectivity (ca. 98%), but the lowest activity. For the palladium catalyst, the influence of the precursor salt and of the reduction temperature on the activity and selectivity were studied. The following activity series was obtained: PdN-423 > PdCl-673 > PdCl-373> PtCl-673 > RhCl-673 >> RuCl-673. As determined by XPS, differences in activity could be attributed, at least in part, to electronic effects.
  • Termocromismo em soluções de alcóxidos de Vanádio(IV): uma abordagem pela modelagem molecular Artigo

    Freitas, Alexandre C. de; Westrup, Kátia C. M.; Nunes, Giovana G.; Gulin, Denis J.; Haiduke, Roberto L. A.; Soares, Jaísa F.; Sá, Eduardo L. de

    Resumo em Inglês:

    The thermochromic behavior exhibited by vanadium(IV) alkoxides, [V2(μ-OPr i)2(OPr i) 6] and [V2(μ-ONep)2(ONep)6 ], OPr i = isopropoxide and ONep = neopentoxide, was studied by molecular modeling using DFT, TDDFT and INDO/S methods. The vibrational and electronic spectra calculated for [V2(μ-OPr i)2(OPr i) 6] were very similar to the experimental data registered for crystalline samples of the complex and for its solutions at low temperature (< 210 K), while spectra recorded at high temperature (> 315 K) were compatible with those calculated for the monomeric form, [V(OPr i)4]. These results consistently point to a monomer/dimer equilibrium as an explanation for the solution thermochromism of {V(OPr i)4}n. In spite of the structural similarity between [V2(μ-ONep)2(ONep)6 ] and [V2(μ-OPr i)2(OPr i) 6] in the solid state, the thermochromic behavior of the former could not be explained by the same model, and the possibility of tetranuclear aggregation at low temperatures was also investigated.
  • Acilação de Friedel-Crafts do 2-metoxinaftaleno usando o ácido dodecafosfotúngstico suportado em sílica (HPW/SiO2) como catalisador e acetonitrila como solvente Artigo

    Santos, Gil Luciano Guedes dos; Silva, Creuza Souza; Cardoso, Luiz Augusto Martins

    Resumo em Inglês:

    The synthesis of fine chemicals intermediates using Friedel-Crafts acylation is one of the most important methods in chemical technology. In this work, the acylation of 2-methoxynaphthalene with acetic anhydride using a silica-supported dodecatungstophosphoric acid catalyst (HPW/SiO2) and acetonitrila as solvent was studied, showing that this reaction is a feasible alternative to produce intermediaries to replace the current methods of production. The reactions using acetonitrile solvent showed yields greater than or equal to the reactions using traditional solvents such as nitrobenzene and dichloroethane. Finally, the modified Eley-Rideal mechanism was proposed to elucidate the experimental data obtained.
  • Desenvolvimento e caracterização de nanocápsulas de poli (L-lactídeo) contendo benzocaína Artigo

    Melo, Nathalie Ferreira Silva de; Grillo, Renato; Rosa, André Henrique; Fraceto, Leonardo Fernandes; Dias Filho, Newton Luiz; Paula, Eneida de; Araújo, Daniele Ribeiro de

    Resumo em Inglês:

    In this paper we describe the preparation poly (L-lactide) (PLA) nanocapsules as a drug delivery system for the local anesthetic benzocaine. The characterization and in vitro release properties of the system were investigated. The characterization results showed a polydispersity index of 0.14, an average diameter of 190.1± 3 nm, zeta potential of -38.5 mV and an entrapment efficiency of 73%. The release profile of Benzocaine loaded in PLA nanocapsules showed a significant different behavior than that of the pure anesthetic in solution. This study is important to characterize a drug release system using benzocaine for application in pain treatment.
  • Emissões naturais e antrópicas de metais e nutrientes para a bacia inferior do rio de contas, Bahia Artigo

    Paula, Francisco C. F. de; Lacerda, Luiz Drude de; Marins, Rozane V.; Aguiar, José E.; Ovalle, Álvaro R. C.; Falcão Filho, Cézar A. T.

    Resumo em Inglês:

    Emission factors of anthropogenic activities and natural processes were used to estimate nutrients and metals loads to the Contas River lower basin, Southern Bahia, Brazil. Among natural sources, emission from soil leaching is larger for N, Cu and Pb. Atmospheric deposition is the major natural source of P, Zn, Cd and Hg. Among anthropogenic sources, agriculture is the major source of N, Cu and P. Urban sources are the major contributors to the other elements. Present anthropogenic land uses are already responsible for 78 and 99% of total N and P loads and about 50% of total Cu and Hg.
  • Comparison of gas chromatographic and gravimetric methods for quantization of total fat and fatty acids in foodstuffs

    Aued-Pimentel, Sabria; Kus, Mahyara Markievicz Mancio; Kumagai, Edna Emy; Ruvieri, Valter; Zenebon, Odair

    Resumo em Inglês:

    Different methods to determine total fat (TF) and fatty acids (FA), including trans fatty acids (TFA), in diverse foodstuffs were evaluated, incorporating gravimetric methods and gas chromatography with flame ionization detector (GC/FID), in accordance with a modified AOAC 996.06 method. Concentrations of TF and FA obtained through these different procedures diverged (p< 0.05) and TFA concentrations varied beyond 20 % of the reference values. The modified AOAC 996.06 method satisfied both accuracy and precision, was fast and employed small amounts of low toxicity solvents. Therefore, the results showed that this methodology is viable to be adopted in Brazil for nutritional labeling purposes.
  • Nanocompósitos semicondutores ZnO/TiO2: testes fotocatalíticos Artigo

    Silva, Shirley Santana; Magalhães, Fabiano; Sansiviero, Maria Terezinha C.

    Resumo em Inglês:

    Titanium dioxide is an efficient photocatalist, being possible to improve its efficiency with better charge separation which occurs when it is coupled with other semiconductors. Nanometric particles of ZnO were used to impregnate TiO2 P25 in order to optimize its photocatalytic properties. ZnO/TiO2 composites were obtained at different proportions and were characterized by X-ray diffraction (XRD), micro-Raman and diffuse reflectance spectroscopies, measurement of surface area (BET) and scanning electron microscopy (SEM). Raman spectroscopy data revealed a change on the TiO2 surface due the presence of ZnO which was observed by an enlargement of TiO2 peaks and a change on the relation rate between anatase and rutile phases of the composites. The photodegradation of azo-dye Drimaren red revealed better efficiency for ZnO/TiO2 3% nanocomposite and for ZnO pure.
  • Otimização e validação intralaboratorial de método para análise de resíduos de cloranfenicol em leite caprino por cromatografia gasosa com detecção por captura de elétrons (CG/DCE) Artigo

    Silva, Jaff R. da; Silva, Luciana T.; Druzian, Janice I.

    Resumo em Inglês:

    The presence of chloramphenicol residues in goat milk can cause toxic effects in the population. The present work consists of the optimization and validation of analytical methodology for determination of chloramphenicol residues in goat milk by GC/ECD. The extraction was made with ethyl acetate and the clean-up with SPE-C18. The identification was made by comparison of retention time and GC/MS, and the quantification by external standard. The method was selective, linearity (0.998), precise (5.8-13.4%), exact (69.87-73.71%) and robust. The LOD and LOQ of method were 0.030 and 0.10 μg/kg, respectively. The method was efficiently for analysis of chloramphenicol in goat milk.
  • A qualidade de água como indicador de uso e ocupação do solo: bacia do Gama - Distrito Federal Artigo

    Moura, Luiz Henrique Amorim; Boaventura, Geraldo Resende; Pinelli, Marcelo Pedrosa

    Resumo em Inglês:

    The spread of Brasília isn't accompanied by correct support of land occupation, situation that is reflected in water quality. Under the optics of land use and occupation, working with multivariate statistics as main tool, water physical and chemical quality of Gama Catchment were assessed. During two years samples were collected and analyzed for 24 parameters. The statistical analysis showed the influence of civil buildings, agricultural activities and the best statistical parameters to a quickly assessment: nitrate, ammonia, suspended solids and aluminium.
  • Chemical composition and antibacterial activities from the essential oils of myrtaceae species planted in Brazil

    Silva, Cleber J.; Barbosa, Luiz C. A.; Demuner, Antonio J.; Montanari, Ricardo M.; Pinheiro, Antônio L.; Dias, Iara; Andrade, Nélio J.

    Resumo em Inglês:

    The essential oils of seven Myrtaceae species were investigated for its chemical composition and antibacterial activity. The volatile oils were characterized by a high content of monoterpenoids of which 1,8-cineole (88.0, 65.0 and 77.0% for Melaleuca hypericifolia, Callistemon viminalis and Callistemon citrinus respectively), terpinen-4-ol (47.0 and 49.8% for Melaleuca thymifolia and Callistemon polandii respectively) and α-pinene (54.5% for Kunzea ericoides) were the major components. The oil from M. linariifolia was characterized by a high concentration of methyleugenol (87.2%). The oil from Melaleuca thymifolia was the most active, exhibiting high antimicrobial activity against all tested bacteria.
  • Determination of Ni(II) in metal alloys by spectrophotometry UV-Vis using dopasemiquinone

    Barreto, Wagner José; Barreto, Sonia Regina Giancoli; Scarminio, Ieda Spacino; Ishikawa, Dílson Norio; Soares, Miriam de Fátima; Proença, Marcus Vinícius Brás de

    Resumo em Inglês:

    A spectrophotometric method was proposed for Ni(II) determination in alloys using a dopa-semiquinone (L-1) to form [Ni(II)(L1-)3]1-, ε = 9.3 x 10³ L mol-1 cm-1. The optimal conditions for the determination were: wavelength 590 nm, temperature 25 °C, reaction time 45 min and pH 7.5. The Beer's law was obeyed for nickel from 3.33 x 10-5 to 1.78 x 10-4 mol L-1. The method was applied to complex samples, such as inox, nickel-titanium and cobalt-chromium alloys. A study of the potential interferents revealed that Mn was the major interferent. The limit of detection and quantification were 2.88 x 10-5 mol L-1 and 3.06 x 10-5 mol L-1, respectively.
  • Determination of cetirizine in tablets and compounded capsules: comparative study between CE and HPLC

    Bajerski, Lisiane; Sangoi, Maximiliano da Silva; Barth, Thiago; Diefenbach, Isabel Fração; Dalmora, Sérgio Luís; Cardoso, Simone Gonçalves

    Resumo em Inglês:

    A capillary electrophoresis (CE) method was developed and validated for determination of cetirizine dihydrochloride in tablets and compounded capsules. The electrophoretic separation was performed in an uncoated fused-silica capillary (40 cm x 50 μm i.d.) using 20 mmol L-1 sodium tetraborate buffer (pH 9.3) as background electrolyte, a hydrodinamic sample injection at 50 mBar for 5 s, 20 KV applied voltage at 25 °C, and detection at 232 nm. The proposed method was compared with the high performance liquid chromatographic (HPLC) method previously validated for this drug, and statistical analysis showed no significant difference between the techniques.
  • Determinação de compostos fenólicos por cromatografia líquida de alta eficiência isocrática durante estacionamento da erva-mate Artigo

    Dutra, Fabiana L. Goularte; Hoffmann-Ribani, Rosemary; Ribani, Marcelo

    Resumo em Inglês:

    Different phenolic compound, 5- caffeoylquinic acid (5-CQA), caffeic acid (AC) and rutin (Ru) contents of yerba-mate (Ilex paraguariensis) Brazilian samples of 06 different regions of São Mateus - Paraná, during natural and accelerated industrial storage, were evaluated. For quantification, a reverse phase HPLC isocratic method was developed and validated using methanol:water (35:65 v/v) acidified with 0.5% acetic acid as mobile phase and a photodiode array detector. The six sample global average contents were (34.90 and 36.10 mg g-1) for 5-CQA, (0.18 mg g-1 and 0.23 mg g-1) for AC and (7.12 and 7.18 mg g-1) for Ru, respectively, for the natural and accelerated storage systems. The results showed that the 5-CQA and Ru content are kept constant during the storage while AC content increase only during accelerated storage.
  • Determination of phenobarbital in human plasma by a specific liquid chromatography method: application to a bioequivalence study

    Dalmora, Sérgio Luiz; Sangoi, Maximiliano da Silva; Nogueira, Daniele Rubert; D'Avila, Felipe Bianchini; Moreno, Ronílson Agnaldo; Sverdloff, Carlos Eduardo; Oliveira, Rogério Antonio de; Borges, Ney Carter

    Resumo em Inglês:

    A liquid chromatography method was developed and validated for the determination of phenobarbital in human plasma using phenytoin as internal standard. The drugs were extracted from plasma by liquid-liquid extraction and separated isocratically on a C12 analytical column, maintained at 35 ºC, with water:acetonitrile:methanol (58.8:15.2:26, v/v/v) as mobile phase, run at a flow rate of 1.2 mL/min with detection at 205 nm. The method was linear in the range of 0.1-4 μg/mL (r²=0.9999) and demonstrated acceptable results for the precision, accuracy and stability studies. The method was successfully applied for the bioequivalence study of two tablet formulations (test and reference) of phenobarbital 100 mg after single oral dose administration to healthy human volunteers.
  • Composição química dos componentes voláteis de Capsicodendron dinisii Schwancke (Canellaceae) Artigo

    Torres, Edson; Wisniewski Jr, Alberto; Simionatto, Edésio L.

    Resumo em Inglês:

    The volatile components of the stem bark of Capsicodendron dinisii were obtained by hydrodistillation using a modified Clevenger-type apparatus. The chemical compounds were identified using the arithmetic index and confirmed by GC-MS. Twenty-three compounds suggest the identified representing almost 90% of the total oil composition. Limonene (68.5%) was the major compound found. The stereochemistry of limonene was determined and was found to be represented by (+)-limonene (94%) and (-)-limonene (6%). The presence of drimenol (0.7%), a drimane sesquiterpenoid, confirmed the volatile components characteristics of the Canellaceae family.
  • Nanocompósitos de poliuretana termoplástica e nanotubos de carbono de paredes múltiplas para dissipação eletrostática Artigo

    Lavall, Rodrigo L.; Sales, Juliana A. de; Borges, Raquel S.; Calado, Hallen D. R.; Machado, José C.; Windmöller, Dario; Silva, Glaura G.; Lacerda, Rodrigo G.; Ladeira, Luiz O.

    Resumo em Inglês:

    Polyurethane/multi-walled carbon nanotube (MWCNT) nanocomposites have been prepared with nanotube concentrations between 0.01 wt% and 1 wt%. MWCNT as-synthesized samples with ~74 nm diameter and ~7 μm length were introduced by solution processing in the polyurethane matrix. Scanning electron microscopy (SEM) images demonstrated good dispersion and adhesion of the CNTs to the polymeric matrix. The C=O stretching band showed evidence of perturbation of the hydrogen interaction between urethanic moieties in the nanocomposites as compared to pure TPU. Differential scanning calorimetry and positron anihilation lifetime spectroscopy measurements allowed the detection of glass transition displacement with carbon nanotube addition. Furthermore, the electrical conductivity of the nanocomposites was significantly increased with the addition of CNT.
  • Composição química de óleos essenciais de espécies de Aniba e Licaria e suas atividades antioxidante e antiagregante plaquetária Artigo

    Alcântara, Joelma Moreira; Yamaguchi, Klenicy K. de Lima; Veiga Junior, Valdir F. da; Lima, Emerson Silva

    Resumo em Inglês:

    Leaves and stems from Aniba panurensis (Meisn.) Mez, Aniba rosaeodora Ducke and Licaria martiniana (Mez) Kosterm. were collected in the Reserva Florestal Adolpho Ducke-AM and their essential oils were obtained by hydrodistillation procedures. The oils were analyzed by GC-FID and GC-MS resulting on fifty and six compounds being identified. The major components were linalool in A. rosaeodora, and β-caryophyllene in A. panurensis and L. martiniana. At qualitative assays the oils showed antioxidant and antiplatelet activities, but only weak activities were found at quantitative spectrometric assays.
  • Determinação de corantes marcadores do tipo azo e antraquinona em combustíveis por cromatografia líquida com detecção eletroquímica Artigo

    Trindade, Magno Aparecido Gonçalves; Rinaldo, Daniel; Vilegas, Wagner; Zanoni, Maria Valnice Boldrin

    Resumo em Inglês:

    An analytical method based on high-performance liquid chromatography with electrochemical detection has been developed and applied to the determination of Solvent blue 14 (SA-14) and Solvent red 24 (SV-24) in fuel samples. The dyes were better separated on C18 column, using a mobile phase composed of acetonitrile and ammonium acetate (90:10, v/v). Detection was carried out at an oxidation potential of +0.85V. The detector response was linear at concentration range of 7.50×10-8 - 1.50×10-6 mol L-1 (r = 0.997) for SA-14 and SV-24, respectively. The method was used to quantify these dyes in fuels samples with satisfactory accuracy and precision.
  • Tecnologia de nanocristais em fármacos Revisão

    Durán, Nelson; Durán, Marcela; Tasic, Ljubica; Marcato, Priscyla D.

    Resumo em Inglês:

    The use of poorly water soluble molecules in pharmaceutical area has grown. Since these molecules exhibit low oral bioavailability, they are not used in intravenous administrations. Therefore, it is necessary to develop their new formulations with the aim to increase their oral bioavailabilities as to enable intravenous applications. One of the few possibilities in achieving this is a nanonization process that can produce crystals smaller than 1 μm by high pressure homogenization and without use of organic solvents. This mini-review describes technical aspects of the nanocrystal production, morphological aspects (polymorphisms), the market relevance of the nanocrystals products that are already in clinical phase or at the market, as well as, perspectives for the near future.
  • Hidróxidos duplos lamelares: nanopartículas inorgânicas para armazenamento e liberação de espécies de interesse biológico e terapêutico Revisão

    Cunha, Vanessa R. R.; Ferreira, Ana Maria da C.; Constantino, Vera R. L.; Tronto, Jairo; Valim, João B.

    Resumo em Inglês:

    Studies about the inorganic nanoparticles applying for non-viral release of biological and therapeutic species have been intensified nowadays. This work reviews the preparation strategies and application of layered double hydroxides (LDH) as carriers for storing, carrying and control delivery of intercalated species as drugs and DNA for gene therapy. LDH show low toxicity, biocompatibility, high anion exchange capacity, surface sites for functionalization, and a suitable equilibrium between chemical stability and biodegradability. LDH can increase the intercalated species stability and promote its sub-cellular uptake for biomedical purposes. Concerning the healthy field, LDH have been evaluated for clinical diagnosis as a biosensor component.
  • Metabólitos secundários de origem vegetal: uma fonte potencial de fármacos antitrombóticos Revisão

    Chaves, Douglas Siqueira de Almeida; Costa, Sônia Soares; Almeida, Ana Paula de; Frattani, Flávia; Assafim, Mariane; Zingali, Russolina Benedeta

    Resumo em Inglês:

    Cardiovascular diseases are responsible for the largest number of deaths among humans worldwide, including heart attacks, strokes, and thrombosis. The treatment of thrombosis is generally through the administration of anticoagulant and/or antiplatelet drugs, which have some clinical limitations. Plants synthesize a wide variety of bioactive metabolites in response to different stimuli. This review focuses on a number of molecules of vegetal origin belonging to different chemical classes, with significant anticoagulant and antiplatelet effects. Their promising antithrombotic profile confirms the potential of natural products as a source of lead molecules for drug development in the prevention and treatment of thrombosis.
  • Produção, propriedades e aplicação de celulases na hidrólise de resíduos agroindustriais Revisão

    Castro, Aline Machado de; Pereira Jr, Nei

    Resumo em Inglês:

    Cellulases have been intensively studied in the past few years, due to the interests in biofuels production from lignocellulosic materials, since they permit maintaining mild conditions during the conversion process. These enzymes can be produced by a broad variety of naturally occurring microorganisms, such as from genera Aspergillus, Trichoderma, Penicillium and Humicola. Targeting the increasing of expression levels, molecular biology tools have been used for heterologous genes insertion in host cells, e. g., Pichia pastoris and Escherichia coli. Enzymes from fungal cellulolytic complex usually act best at pH between 4 and 5 under temperatures from 40 to 60 °C and can be used for either sequential (SHF) or simultaneous (SSF) hydrolysis together alcoholic fermentation. In this review, the main raw materials for production of cellulases are identified, as well as the state of art of enzymes' properties, production and main applications.
  • Câmaras climáticas para o envelhecimento acelerado: ação de microambientes sobre bens culturais Nota Técnica

    Paiva, Renato Inhasz; Rocha, José Roberto Caetano da; Cavicchioli, Andrea; Lopes, Fernando Silva; Faria, Dalva Lúcia Araújo de

    Resumo em Inglês:

    Environmental chambers were designed for the accelerated ageing of materials used in artistic artifacts to study the synergistic action of temperature, humidity, UV and visible radiation and gaseous pollutants. Two inox-steel/PTFE compartments are kept under controlled temperature and relative humidity, whose values are transmitted to a PC, which stores, plots in real time and continuously feedback heating and humidifying devices through logical signals. A borosilicate, or quartz, window allows the irradiation inside the chamber from an external source. A flow of purified air purges the chamber and conveys selected pollutants from an external source. Each independent compartment works under either stationary or cyclic conditions.
  • Comparação entre métodos compostos no cálculo de afinidades por próton e elétron em sistemas moleculares Nota Técnica

    Lima, José Carlos B. de; Morgon, Nelson H.

    Resumo em Inglês:

    The CBS-4M, CBS-QB3, G2, G2(MP2), G3 and G3(MP2) model chemistry methods have been used to calculate proton and electron affinities for a set of molecular and atomic systems. Agreement with the experimental value for these electronic properties is quite good considering the uncertainty in the experimental data. A comparison among the six theories using statistical analysis (average value, standard deviation and root-mean-square) showed a better performance of CBS-QB3 to obtain these properties.
  • Desenvolvimento e validação de método analítico por cromatografia líquida de alta eficiência (CLAE) para determinação de associação de ampicilinas em pó liofilizado para injeção Nota Técnica

    Cione, Ana Paola Prata; Liberale, Márcio José; Silva, Paulo Marcos da

    Resumo em Inglês:

    An analytical method has been developed and validated for the determination of an association of ampicillins in a lyophilized powder for injection by HPLC. The advantage of chromatographic method other than the microbiological one is that, it is possible to monitor precisely, out-of-specification results in quality control processes and also during stability studies, in which an association of ampicillins is present. The proposed HPLC method was developed by using forced degraded samples, in order to reach a selective analysis of ampicillins when in the presence of their degradation products. It was possible to detect benzatine and through indirect calculation, to determine the ampicillin sodium in the drug sample. The method showed to be selective, accurate, precise, robust and linear (from 45.92 to 36.04 μg mL-1 of total ampicillin and from 14.53 to 43.28 μg mL-1 of benzatine). The accuracy determined from recovery test, gave results in the range of 99.41% of total ampicillin to 100.31% of benzatine. Hence, it can be concluded that the proposed HPLC method is applicable for ampicillins determination.
  • Development and validation of RP-LC and uv spectrophotometric methods to assay bromopride in oral and injectable solutions

    Fontana, Márcia Camponogara; Hurtado, Felipe Kellermann; Wrasse, Micheli; Boligon, Aline Augusti; Venturini, Tarcieli Pozzebon; Rolim, Clarice Madalena Bueno; Beck, Ruy Carlos Ruver

    Resumo em Inglês:

    A reversed-phase liquid chromatographic (LC) and ultraviolet (UV) spectrophotometric methods were developed and validated for the assay of bromopride in oral and injectable solutions. The methods were validated according to ICH guideline. Both methods were linear in the range between 5-25 μg mL-1 (y = 41837x - 5103.4, r = 0.9996 and y = 0.0284x - 0.0351, r = 1, respectively). The statistical analysis showed no significant difference between the results obtained by the two methods. The proposed methods were found to be simple, rapid, precise, accurate, and sensitive. The LC and UV methods can be used in the routine quantitative analysis of bromopride in oral and injectable solutions.
  • Utilização e recuperação de sílica gel impregnada com nitrato de prata Nota Técnica

    Andreão, Patrícia S. S.; Giacomini, Rosana A.; Stumbo, Alexandre M.; Waldman, Walter R.; Braz-Filho, Raimundo; Ligiéro, Carolina B. P.; Miranda, Paulo C. M. L.

    Resumo em Inglês:

    Argentation chromatography is used to increase the selectivity of the chromatographic process, chiefly in the resolution of complex mixtures of nonpolar substances. Although efficient, this technique generates residues containing heavy metal which makes its discarding through common procedures impracticable. In the present work a simple method for recycling of silica, and also silver, from argentation chromatography is described. This procedure uses initially a treatment of H2O2/HNO3, with subsequent treatment with H2O2/H2SO4 , allowing an efficient recycling of both components. This methodology is simple, costless, removes impurities efficiently, and does not modify retention parameters nor specific surface in a significant way.
  • Sistema limpo em linha para extração em fase sólida de contaminantes emergentes em águas naturais Nota Técnica

    Sodré, Fernando F.; Locatelli, Marco Antonio F.; Jardim, Wilson F.

    Resumo em Inglês:

    A solid-phase in-line extraction system for water samples containing low levels of emerging contaminants is described. The system was specially developed for large volume samples (up to 4 L) using commercial solid-phase extraction (SPE) cartridges. Four sets containing PTFE-made connectors, brass adapters and ball valves were used to fit SPE cartridges and sample bottles to a 4-port manifold attached to a 20 L carboy. A lab-made vacuum device was connected to the manifold cap. The apparatus is robust and less expensive than the typical available system. Its also provides less experimental handling, avoiding cross contamination and sample losses.
  • O valor energético dos alimentos: exemplo de uma determinação experimental, usando calorimetria de combustão Educação

    Santos, Rui C.

    Resumo em Inglês:

    The energies involved in the combustion, under atmosphere of oxygen, of breakfast cereals and dehydrate powdered whole milk samples, were determined by combustion calorimetry. This practical work, in the field of human nutrition, involved the characterization of the nutritional composition and the combustion of samples of the two foods that are part of the alimentary diet, namely, at breakfast. The obtained results allowed to assess the energy value printed in the foods labels and discuss the way those values are estimated.
  • Simulação Monte Carlo no ensino de luminescência e cinética de decaimento de estados excitados Educação

    Winnischofer, Herbert; Araújo, Márcio Peres de; Dias Júnior, Lauro Camargo; Novo, João Batista Marques

    Resumo em Inglês:

    A software based in the Monte Carlo method have been developed aiming the teaching of important cases of mechanisms found in luminescence and in excited states decay kinetics, including: multiple decays, consecutive decays and coupled systems decays. The Monte Carlo Method allows the student to easily simulate and visualize the luminescence mechanisms, focusing on the probabilities of the related steps. The software CINESTEX was written for FreeBASIC compiler; it assumes first-order kinetics and any number of excited states, where the pathways are allowed with probabilities assigned by the user.
  • Contribuição da fitoquímica para o desenvolvimento de um país emergente Assuntos Gerais

    Braz Filho, Raimundo

    Resumo em Inglês:

    The sustainable development of an emergent country is dependent on a consistent scientific, technologic and innovative policy, on nature and biodiversity, on a rational exploration of natural resources to feeding, social advance and economical aim along with maintenance of health and diseases treatment. Phytochemical investigations may be used to contribute with development throughout undergraduate and graduate career preparing professionals with qualification to these activities, as researcher and professor, including discovering and divulgation of new scientific knowlegments. The role of organic compounds produced by secondary metabolism of plants in the development of new drugs is presented (e. g.) throughout exposition using examples of features involved in this activity, since the recognition of a plant-derived popular medicine, until the laboratory semi-synthesis of its main constituents. Several aspects related to the use of some vegetable species in treatment of many tropical diseases are pointed. Economical and social importance of isolation, structural characterization, pharmacological investigation and chemical transformations of new natural organic substances isolated from the plants are related.
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