Química Nova, Volume: 33, Issue: 2, Published: 2010
  • Há futuro para as revistas das sociedades científicas? Editorial

    Torresi, Susana I. Córdoba de; Pardini, Vera L.; Ferreira, Vitor F.; Andrade, Jailson B. de
  • Preliminary study of insect attraction by a mixture of semiochemicals containing 1,2,4-Trimethoxybenzene in domestic citric-culture

    Alves, Ana Paula L.; C. Júnior, José Augusto B. de; Slana, Glaucia B. A.; Cardoso, Jari N.; Lopes, Rosangela S. C.; Lopes, Claudio C.

    Abstract in English:

    In this work we describe a new efficient strategy for the preparation of 1,2,4-trimethoxybenzene (3) in 56% overall yield. The compound 3 was used in a preliminary study of insect attraction by a mixture of semiochemicals called TIV, composed of indol (1), vanillin (2) and 1,2,4-trimethoxybenzene (3), in eight Mc Phail style traps installed at a domestic orchard of citric-culture, containing 120 trees not infected by plagues in Bom Jesus Farm, located next to a patch of the Atlantic Forest, at Silva Jardim, Rio de Janeiro, Brazil.
  • Effect of molecular sieves 3A, 4A, 5A and 13X incorporation on the chitosan/poly(vinyl alcohol) composites membranes Artigo

    Vicentini, Denice Schulz; Lima, João Cardoso de; Laranjeira, Mauro Cesar Marghetti

    Abstract in English:

    The composite membranes prepared via incorporation of 12.5% of molecular sieves 3A, 4A, 5A and 13X into chitosan/poly(vinyl alcohol) (1:1). The composite membranes were immersed in the cross-linker sulfuric acid in order to acquire high proton conductivity for applications in electrolytes in PEMCF and DMF. The influence of the molecular sieves on the structural, optical, thermal, mechanical, morphologic and protonic conductivity properties and water/methanol swelling degree of membranes were investigated.
  • Volatile compounds from Rosmarinus officinalis L. and Baccharis dracunculifolia DC. Growing in southeast coast of Brazil

    Boix, Yilan Fung; Victório, Cristiane Pimentel; Lage, Celso Luiz Salgueiro; Kuster, Ricardo Machado

    Abstract in English:

    Chemical composition of leaf volatiles of Rosmarinus officinalis and Baccharis dracunculifolia cultured in Southeast of Brazil has been characterized by GC/MS after simultaneous distillation-extraction. The main components in volatiles of these species showed in common α-pinene, myrcene, 1,8 cineole and camphor. Camphor was the major component among volatiles of B. dracunculifolia and R. officinalis with concentrations exceeding 25%. B. dracunculifolia volatiles possessed more sesquiterpenes (21.4%) than R. officinalis (16.7%), such as caryophyllene (1.9%) and α-humulene (0.4%). Lower concentrations of nerolidol and spathulenol were achieved in volatiles of B. dracunculifolia. Considering both species, there was a predominance of monoterpenes.
  • Influence of different water-ethanol solvent systems on the spectroscopic and physico-chemical properties of the macrocyclic compounds pheophytin and chlorophyll α Artigo

    Moreira, Leonardo M.; Rodrigues, Máira R.; Oliveira, Hueder P. M. de; Lima, Adriana; Soares, Rafael R. S.; Batistela, Vagner R.; Gerola, Adriana P.; Hioka, Noboru; Severino, Divinomar; Baptista, Mauricio S.; Machado, Antônio Eduardo da Hora

    Abstract in English:

    This work focus on the influence of solvent on the photophysical properties of chlorophyll α and pheophytin. Both compounds are related to the photosynthesis process and are considered prototypes of photosensitizers in Photodynamic Therapy. Fluorescence measurements were developed using water/ethanol mixtures at different compositions, since both solvents could be employed in biological applications. The spectroscopic properties of these compounds undergo profound changes depending on water content in the ethanol due to auto-aggregation processes. The major hydrophobicity and the lower dielectric constant of ethanol when compared with water precluded significantly the auto-aggregation process of these compounds.
  • Production by emulsion method of alginate microparticles containing inactivated Flavobacterium columnare for oral fish vaccination Artigo

    Sacchetin, Priscila Soares Costa; Moraes, Ângela Maria; Leal, Carlos Augusto Gomes; Figueiredo, Henrique César Pereira

    Abstract in English:

    Alginate microparticles were prepared by an emulsion method aiming oral controlled release of antigens to fish. The effects of emulsification temperature and impeller type on particle morphology, average diameter, and size distribution were evaluated. Microparticles contaning formalin-killed Flavobacterium columnare cells (a model antigen) were prepared and characterized regarding bacterial release and particle stability when exposed to Nile tilapia (Oreochromis niloticus) typical gastrointestinal conditions. This methodology allowed the production of microparticles containing up to 14.3 g/L of bacterin, stable at a pH range from 2.0 to 9.0 for 12 h and smaller than 35 μm.
  • Preparation and characterization oF Ru-Sn/Al2O3 catalysts for the hydrogenation of fatty acid methyl esters

    Mazzieri, Vanina A.; Sad, Mario R.; Vera, Carlos R.; Pieck, Carlos L.; Grau, Ricardo

    Abstract in English:

    Ru-Sn/Al2O3 catalysts with different Sn loadings were prepared by the coimpregnation method. Several characterization techniques such as TPR, pyridine TPD and catalytic tests for dehydrogenation and hydrogenolysis were used to evaluate and compare such catalysts. TPR results indicate that Sn is deposited both onto the support and as species strongly interacting with Ru. Such non selective deposition modifies the acid and metallic functions of the catalysts. Both total acidity and acid strength distribution are affected: total acidity decreases and new sites of lower acid strength are created. Both dehydrogenating and hydrogenolytic activities are strongly diminished by the addition of Sn. Results of catalytic tests for methyl oleate hydrogenation indicate that methyl stearate is the main product, with only minute amounts of oleyl alcohol produced, and that the addition of Sn diminishes the hydrogenation activity.
  • Effect of nitrate application on reduction of biogenic sulphide under different initial concentrations of nitrate and sulphate-reducing bacteria Artigo

    Sousa, Kally Alves de; Cammarota, Magali Christe; Sérvulo, Eliana Flávia Camporese

    Abstract in English:

    The effect of sodium nitrate application in the reduction of biogenic sulphide was evaluated through a 2k complete factorial design, using as variable response the production of sulfide at intervals of incubation of 7, 14 and 28 days. The most effective condition for reducing the sulphide production (final concentrations from 0.4 to 1.6 mg S2- L-1) was obtained with an initial population of sulphate-reducing bacteria and nitrate-reducing bacteria of 10(4) MPN mL-1 and 427.5 mg L-1 nitrate. The results also suggested that the applications of nitrate to control the process of souring should follow a continuous scheme.
  • Plasmid DNA damage induced by singlet molecular oxygen released from the naphthalene endoperoxide DHPNO2 and photoactivated methylene blue

    Berra, Carolina Maria; Menck, Carlos Frederico Martins; Martinez, Glaucia Regina; Oliveira, Carla Santos de; Baptista, Maurício da Silva; Di Mascio, Paolo

    Abstract in English:

    To investigate oxidative lesions and strand breaks induction by singlet molecular oxygen (¹O2), supercoiled-DNA plasmid was treated with thermo-dissociated DHPNO2 and photoactivated-methylene blue. DNA lesions were detected by Fpg that cleaves DNA at certain oxidized bases, and T4-endoV, which cleaves DNA at cyclobutane pyrimidine dimers and apurinic/apyrimidinic (AP) sites. These cleavages form open relaxed-DNA structures, which are discriminated from supercoiled-DNA. DHPNO2 or photoactivated-MB treatments result in similar plasmid damage profile: low number of single-strand breaks or AP-sites and high frequency of Fpg-sensitive sites; confirming that base oxidation is the main product for both reactions and that ¹O2 might be the most likely intermediate that reacts with DNA.
  • Indole alkaloids from the bark of Aspidosperma vargasii and A. desmanthum Artigo

    Henrique, Marycleuma Campos; Nunomura, Sergio Massayoshi; Pohlit, Adrian Martin

    Abstract in English:

    Fractionation of extracts resulted in isolation and identification of indole alkaloids ellipticine and N-methyltetrahydroellipticine from A. vargasii and aspidocarpine from A. desmanthum. Identification of these compounds was achieved based on IR, MS, ¹H, 13C and 2-D NMR data and comparison to data in the literature.
  • Optimization of analytic methodologies for quantifying flavonoids of Bauhinia cheilantha (Bongard) Steudel Artigo

    Peixoto Sobrinho, Tadeu José da Silva; Gomes, Tiago de Lima Barros; Cardoso, Késsio Carlos de Macedo; Amorim, Elba Lúcia Cavalcanti de; Albuquerque, Ulysses Paulino de

    Abstract in English:

    The present study examined the optimization of stabilization and extraction processes of the flavonoids of Bauhinia cheilantha (Bongard) Steudel. Four drying temperatures (room temperature, 40, 60 and 80 ºC) and seven extraction systems (distilled water, 100% methanol, 80% methanol, 100% ethanol, 80% ethanol, 80% acetone and 60% acetone) were examined. The results demonstrated a reduction in flavonoid levels with increasing drying temperatures; and 80% acetone, 80% ethanol, and methanol p.a extraction systems were found to be most efficient and its weren't differents statisticaly (p<0.05).
  • Antifungal iridoids, triterpenes and phenol compounds from Alibertia myrciifolia Sprunge Ex. Schum

    Luciano, João Henrique S.; Lima, Mary Anne S.; Silveira, Edilberto Rocha; Vasconcelos, Ilka Maria; Fernandes, Georgia Sampaio; Souza, Elnatan Bezerra de

    Abstract in English:

    The new iridoid glucoside 10-O-vanilloyl-geniposidic acid has been isolated from the aerial parts of Alibertia myrciifolia along with hydroxyhopanone, 3α,22-dihydroxyhopane, ursolic acid, luteolin-3´,4´-dimethyl ether, caffeic acid and geniposidic acid. The structures of the isolated compounds were determined by means of mass spectrometry and nuclear magnetic resonance spectral analyses. The antifungal activities of the iridoids 10-O-vanilloyl-geniposidic acid and geniposidic acid were evaluated against the phytopathogenic fungi strains Colletotrichum gloeosporioides, Fusarium solani and Aspergillus niger.
  • Orange oil/water nanoemulsions prepared by high pressure homogenizer Artigo

    Kourniatis, Loretta R.; Spinelli, Luciana S.; Mansur, Claudia R. E.; González, Gaspar

    Abstract in English:

    The objective of this work was to use the high-pressure homogenizer (HPH) to prepare stable oil/water nanoemulsions presenting narrow particle size distribution. The dispersions were prepared using nonionic surfactants based on ethoxylated ether. The size and distribution of the droplets formed, along with their stability, were determined in a Zetasizer Nano ZS particle size analyzer. The stability and the droplet size distribution in these systems do not present the significant differences with the increase of the processing pressure in the HPH). The processing time can promote the biggest dispersion in the size of particles, thus reducing its stability.
  • Employ of silica gel organically modified and ionically imprinted for selective on-line preconcentration of copper ions Artigo

    Ávila, Thiago Carvalho de; Segatelli, Mariana Gava; Beijo, Luiz Alberto; Tarley, César Ricardo Teixeira

    Abstract in English:

    The present work purposes the preparation of a silica gel sorbent organically modified with 2-aminoethyl-3-aminobutylmethyldimethoxysilane (AAMDMS) and imprinted with Cu2+ ions by means surface imprinting technique and its use for selective on-line sorbent preconcentration of Cu2+ ions with further UV-VIS spectrophotometric determination by flow injection analysis. The Cu2+-imprinted silica gel, when compared with non imprinted silica gel and silica gel, showed from the binary mixture of Cu2+/Ni2+ relative selectivity coefficient (k') of 6.84 and 5.43 and 6.64 and 19.83 for the mixture Cu2+/Pb2+, thus demonstrating higher selectivity of Cu2+-imprinted silica gel towards Cu2+ ions. Under optimized condition, the on-line preconcentration method provided detection limit of 3.4 μg L-1 and linear range ranging from 30.0 up to 300.0 μg L-1 (r = 0.995). The accuracy of method was successfully assessed by analyzing different kind of spiked water samples with recovery values ranging from 92.2 up to 103.0%.
  • Modification of a Brazilian smectite clay with different quaternary ammonium salts

    Delbem, Maria Flávia; Valera, Ticiane S.; Valenzuela-Diaz, Francisco R.; Demarquette, Nicole R.

    Abstract in English:

    In this work, a smectite clay from the State of Paraiba, Brazil, was treated with six different types of ammonium salts, which is an usual method to enhance the affinity between the clay and polymer for the preparation of nanocomposites. The clays, before and after modification, were characterized by X ray diffraction. The conformation of the salts within the platelets of the clay depended on the number of long alkyl chains of the salt. The thermal stability of the clays was also studied. The ammonium salts thermal decomposition was explained in light of their position within the organoclays.
  • Simultaneous determination of serotonin precursors - tryptophan and 5-hidroxytryptophan - in coffee Artigo

    Martins, Ana Carolina C. L.; Silva, Tarliane M.; Gloria, M. Beatriz A.

    Abstract in English:

    Epidemiological studies attributed positive effects in the central nervous system (CNS) to coffee. Among possible active constituents, serotonin, a neurotransmitter in the CNS, is present; but dietary sources do not cross the blood-brain barrier. Tryptophan and 5-hidroxytryptophan (5-HTP) are serotonin precursors and can affect brain concentrations. An ion-pair-HPLC, post-column derivatization with o-phthalaldehyde and fluorimetric detection before and after hydrolysis with NaOH and extraction with methanol:water was developed for the simultaneous determination of these compounds. It was selective, sensitive (LOD = 0.3 and 0.2 μg/mL), precise (91.3 and 94.2% recovery for tryptophan and 5-HTP, respectively), and linear from 0.3 to 40 μg/mL for both compounds. It was applied to green and roasted arabica and robusta coffees.
  • Aromatic compounds from three Brazilian Lauraceae species

    Batista, Andrea Nastri de Luca; Batista Junior, João Marcos; López, Silvia Noelí; Furlan, Maysa; Cavalheiro, Alberto José; Silva, Dulce Helena Siqueira; Bolzani, Vanderlan da Silva; Nunomura, Sergio Massayoshi; Yoshida, Massayoshi

    Abstract in English:

    Phytochemical investigations on three Brazilian Lauraceae species from the Cerrado region of São Paulo State, Ocotea corymbosa (Meins) Mez., O. elegans Mez. and Persea pyrifolia Nees & Mart. ex Nees resulted in the isolation of flavonoids, an ester of the 4-O-E-caffeoylquinic acid, an aromatic sesquiterpene besides furofuran lignans. This is the first chemical study on the leaves of Ocotea elegans and O. corymbosa as well as the first report of non-volatile compounds from Persea pyrifolia.
  • Protease production using agroindustrial residues by thermophilic Bacillus sp in submerged fermentation: optimization of the culture medium using an experimental design approach Artigo

    Ladeira, Silvania Alves; Andrade, Marcela Vicente Vieira; Delatorre, Andréia Boechat; Perez, Victor Haber; Martins, Meire Lélis Leal

    Abstract in English:

    Thermophilic Bacillus sp. SMIA-2, produced protease when grown on apple pectic, whey protein and corn step liquor medium, whose concentration was varied from 3 to 10 gL-1, according to the central composite design 2³. The experiments were conducted in shaker, at 50 °C, 150 rpm and initial pH 6.5. The results revealed that the culture medium affected both, cell growth and enzyme production. After graphical and numerical optimization procedure, the enzyme production reached its maximum value at 30 h fermentation, reaching, approximately, 70 U protein mg-1, suggesting that this process was partially associated to the growth.
  • Evaluation of analytical methods for BTEX analysis in water using extraction by headspace (HS) and solid phase microextraction (SPME) Artigo

    Heleno, Fernanda F.; Lima, Aniel C.; Afonso, Robson J. C. F.; Coutrim, Mauricio X.

    Abstract in English:

    Three analytical methods for the determination of BTEX in water were optimized and validated. With the best method the analytes were extracted of 10 mL of sample with 2.50 g of NaCl in headspace vial of 20 mL by HS and SPME to 40 ºC for 30 min for adsorption and to 250 ºC for 4 min for desorption and were analyzed by GC-MS. The recovery was between 97.9% and 104.3%, and the limit of detection was 2.4 ng L-1 for o-xylene. This method was using to analyze BTEX in water supply and surface water in Ouro Preto city. No sample had concentrations of BTEX above the legislation.
  • Air pollution and emergency admissions for cardiorespiratory diseases in Lisbon (Portugal)

    Alves, Célia A.; Scotto, Manuel G.; Freitas, Maria do Carmo

    Abstract in English:

    Daily records of hospital admissions due to cardiorespiratory diseases and levels of PM10, SO2, CO, NO, NO2, and O3 were collected from 1999-2004 to evaluate the relationship between air pollution and morbidity in Lisbon. Generalised additive Poisson regression models were adopted, controlling for temperature, humidity, and both short and long-term seasonality. Significant positive associations, lagged by 1 or 2 days, were found between markers of traffic-related pollution (CO and NO2) and cardiocirculatory diseases in all age groups. Increased childhood emergency admissions for respiratory illness were significantly correlated with the 1-day lagged SO2 levels coming from industrial activities.
  • Enzymatic modification on rice flour seeking the production of resitant starch Artigo

    Severo, Márcio Garcia; Moraes, Kelly de; Ruiz, Walter Augusto

    Abstract in English:

    The aim of this work was to study the enzymatic modification on rice flour using lipase pancreatic and amyloglucosidase to obtain resistant starch. For this, Response Surface Methodology (RSM) was used to determine the best operating conditions for each enzyme. For lypase pancreatic, the highest value for resistant starch (45%) was achieved within 2 h reaction at pH 7 using an enzyme/substrate ratio of 4% (w/w) and Dp= 100/200 tyler. For amyloglucosidase, optima conditions corresponded to an enzyme/substrate ratio of 0,006 mL/g and Dp= 100/200 tyler at 45 ºC, yielding 57% of resistant starch in 2 h reaction. These results show the potential of using both enzymes to modified rice flour, increasing the resistant starch in about 5.7 folds in relation to the flour without treatment (resistant starch=10.6%).
  • Screening analysis of wines using flow-batch analyzer, UV-VIS spectroscopy and chemometrics Artigo

    Nascimento, Jaqueline Azevedo; Dionísio, Amália Geíza Gama; Nascimento, Elaine Cristina Lima do; Freitas, Sueny Kêlia Barbosa; Araújo, Mário César Ugulino de

    Abstract in English:

    A simple, robust, versatile, high analytical frequency method was proposed to check if a sample of wine is within the range of standards set by the manufacturer, using the UV-VIS spectroscopy, multivariate analysis and a flow-batch analyzer. Two hundred and fifty-two samples of wines were analyzed. The results from the application of Hierachical Cluster Analysis (HCA) to the matrix of the data involving all samples show the formation of fifteen types of wine. A Soft Independent Modelling of Class Analogy (SIMCA) model was constructed and used to classify the samples of the overall forecast. As a result, it is observed that the prediction was performed with a success rate of 99.2% for a confidence level of 95%. This shows that the proposed methodology can be used as an effective tool for classifying of samples of wines.
  • Adsorption of reactive orange 16 from aqueous solutions by synthesized zeolite Artigo

    Carvalho, Terezinha Elizabeth Mendes de; Fungaro, Denise Alves; Izidoro, Juliana de Carvalho

    Abstract in English:

    Coal fly ash, a waste generated in a coal-fired electric power plant, was used to synthesize zeolite by hydrothermal treatment with NaOH solution. This zeolite was used as adsorbent to investigate the adsorption kinetics and isotherm parameters of the reactive orange 16 (RO16) dye from aqueous solutions at different concentrations (1.3-15.4 mg L-1). Three kinetic models, the pseudo-first-order, second-order, and intraparticle diffusion were used to predict the adsorption rate constants. The kinetics of adsorption of the RO16 dye followed pseudo-second-order kinetics. The adsorption isotherm data were closely fitted to the Langmuir equation. Keywords: coal fly ash; zeolite; reactive dye adsorption.
  • Interference of lignin in the quantification of free radicals in the process of composting Artigo

    Fialho, Lucimar Lopes; Silva, Wilson Tadeu Lopes da; Milori, Débora M. B. P.; Simões, Marcelo Luiz; Martin-Neto, Ladislau; Saab, Sérgio da Costa

    Abstract in English:

    In this work was studied composts and their humic acids (HA) to evaluate the use of EPR in the monitoring of the humification. It was observed increase in the concentration of organic free radical (OFR) in all the composts, but in L1 the increase was more significant than L2 and L3. Research more detailed of L1 showed that the lignin is main source of OFR. Then determination of these radicals in material in nature that contains high amount of lignin isn't a good indicator to monitor the humification process in the composting and yes the fraction HA of the composts.
  • Extended Hildebrand solubility approach in the estimation of ketoprofen solubility in ethanol + water cosolvent mixtures

    Gantiva, Mauricio; Martínez, Fleming

    Abstract in English:

    Extended Hildebrand Solubility Approach (EHSA) developed by Martin et al. was applied to evaluate the solubility of ketoprofen (KTP) in ethanol + water cosolvent mixtures at 298.15 K. Calculated values of molar volume and solubility parameter for KTP were used. A good predictive capacity of EHSA was found by using a regular polynomial model in order five to correlate the W interaction parameter and the solubility parameters of cosolvent mixtures (δmix). Nevertheless, the deviations obtained in the estimated solubilities with respect to the experimental solubilities were on the same order like those obtained directly by means of an empiric regression of the logarithmic experimental solubilities as a function of δmix values.
  • Losartan potassium dissolution test for drug release evaluation in pharmaceutical capsules using HPLC and UV spectrophotometry

    Bonfilio, Rudy; Mendonça, Taciane Ferreira; Pereira, Gislaine Ribeiro; Araújo, Magali Benjamim de; Tarley, César Ricardo Teixeira

    Abstract in English:

    This work describes the development and validation of a dissolution test for 50 mg losartan potassium capsules using HPLC and UV spectrophotometry. A 2(4) full factorial design was carried out to optimize dissolution conditions and potassium phosphate buffer, pH 6.8 as dissolution medium, basket as apparatus at the stirring speed of 50 rpm and time of 30 min were considered adequate. Both dissolution procedure and analytical methods were validated and a statistical analysis showed that there are no significant differences between HPLC and spectrophotometry. Since there is no official monograph, this dissolution test could be applied for quality control routine.
  • Photolysis and UV/H2O2 treatment of a synthetic effluent containing food dyes Artigo

    Marmitt, Sandro; Pirotta, Lilian V.; Stülp, Simone

    Abstract in English:

    Food industries employ a lot of synthetic dyes in their products. Most of these dyes are very stable face to the conventional treatments. This work studied the use of advanced oxidation process (AOP) as an alternative to the conventional ones to degrade a synthetic food effluent (photolysis and UV/H2O2 in continuous reactor). The more efficient process was the UV/H2O2 and it presented decoloration and degradation energetic efficiency values equal to 30.775 kWh m-3 and 269.909 kWh m-3, respectively. The color reduction was 96.4% and COD decrease was 38.56%.
  • Determination of sildenafil citrate and tadalafil by ultra performance liquid chromatography with diode-array detection (UPLC-DAD) Artigo

    Ortiz, Rafael Scorsatto; Antunes, Marina Venzon; Linden, Rafael

    Abstract in English:

    A simple ultra-performance liquid chromatographic method for the simultaneous determination of sildenafil citrate and tadalafil was developed and validated. Sample preparation was dissolution in methanol, followed by centrifugation and dilution (1:10) with methanol. Analysis was performed in an Acquity® UPLC system with Acquity® BEH C18 column (2.1 x 50 mm, with 1.7 μm particles). The elution was isocratic with phosphate buffer pH 2.3 and acetonitrile (65:35, v/v) at a flow rate of 0.7 mL/min. The method presented adequate specificity, linearity, precision and accuracy and allowed the determination of the drugs in seized forensic samples.
  • Hydrolysis of Azadirachta indica oil using subcritical water and determination of triacylglycerides and fat acids by HT-HRGC-FID and HRGC-MS Artigo

    Pinto, Jair Sebastião da Silva; Lanças, Fernando Mauro

    Abstract in English:

    The development of modern analytical tools plays an important role in quality control. The main purpose of this study was to explore the use of subcritical water as a versatile analytical tool, employed simultaneously as a reagent and solvent, as well as the application of high temperature-high resolution gas chromatography (HT-HRGC) to develop a procedure for the analysis of triacylglycerides and fatty acids in Azadirachta indica A. Juss. (Neem) oil without the need for solvents, chemical reagents, or catalytic agents. The developed method presented satisfactory results and is in agreement with the concepts of Green Analytical Chemistry (GAC).
  • Study on the efficiency of carbon tetrachloride decomposition in argon thermal plasma and characterization of the formed products Artigo

    Khalaf, Péricles Inácio; Souza, Ivan Gonçalves de; Carasek, Eduardo; Debacher, Nito Angelo

    Abstract in English:

    Decomposition of carbon tetrachloride in a DC thermal plasma reactor was investigated in argon atmosphere. The operational parameters such as plasma torch power and argon flow rate versus CCl4 conversion were examined. The CCl4 net degradation was determined by GC-FID, the chlorine produced was quantified by iodometric titration, the solid carbon was characterised by Raman spectroscopy and by BET analysis. The solid carbon collected inside de plasma reactor was submitted to solid/liquid extraction and the desorbed species were identified by GC-MS.
  • Development of a flotation method for preconcentration-separation of trace amounts of some metal ions in plant tissues prior to their FAAS determinations

    Ghaedi, M.; Shokrollahi, A.; Montazerozohori, M.; Marahel, F.; Soylak, M.

    Abstract in English:

    An efficient flotation method based on the combination of flame atomic absorption spectrometry (FAAS) and separation and preconcentration step for determination of Cr3+, Cu 2+, Co2+, Ni2+, Zn2+, Cd 2+, Fe3+ and Pb2+ ions in various real samples by the possibility of applying bis(2-hydroxyacetophenone)-1,4-butanediimine (BHABDI) as a new collector was studied. The influence of pH, amount of BHABDI as collector, sample matrix, type and amount of eluting agent, type and amount of surfactant as floating agent, ionic strength and air flow rates i.e. variables affecting the efficiency of the extraction system was evaluated. It is ascertained that metal ions such as iron can be separated simultaneously from matrix in the presence of 0.012 mM ligand, 0.025% (w/v) of CTAB to a test sample of 750 mL at pH 6.5. These ions can be eluted quantitatively with 6 mL of 1.0 mol L-1 HNO3 in methanol which lead to the enrichment factor of 125. The detection limits for analyte ions were in the range of 1.3-2.4 ng mL-1. The method has been successfully applied for determination of trace amounts of ions in various real samples.
  • Recent research data on the removal of pharmaceuticals from sewage treatment plants (STP)

    Tambosi, José Luiz; Yamanaka, Leonardo Yassuhiro; José, Humberto Jorge; Moreira, Regina de Fátima Peralta Muniz; Schröder, Horst Friedrich

    Abstract in English:

    Pharmaceutical compounds have been detected in sewage treatment plant (STP) effluents, surface waters and, less frequently, in groundwater and drinking water, all over the world. Different sources are responsible for their appearance in the aquatic environment, however, it is widely accepted that the main sources of this type of pollutant are STP effluents. The adverse effects of pharmaceuticals in the environment include aquatic toxicity, development of resistance in pathogenic bacteria, genotoxicity and endocrine disruption. Thus, the discharge of these compounds to the environment in STP effluents should be minimized.
  • Nanomaterials and the environment Revisão

    Paschoalino, Matheus P.; Marcone, Glauciene P. S.; Jardim, Wilson F.

    Abstract in English:

    The increasing use of nanomaterials in several products in different areas such as electronics, cosmetics, food and drugs has attracted the attention of the scientific community due to unknown properties of these materials, such as the life cycle and the interaction with receptor organisms once they reach the environment. In this context, the present work shows an updated scenario of nanomaterials applications, characterization methods and toxicity evaluation, also addressing important aspects related to the development and application of nanotechnology under the environmental point of view.
  • Biochemical modification of milkfat Revisão

    Nunes, Gisele Fátima Morais; Paula, Ariela Veloso de; Castro, Heizir Ferreira de; Santos, Júlio César dos

    Abstract in English:

    Recent advances for improving physicochemical and nutritional properties of lipids are reviewed, with emphasis on products attaining by biochemical processing of natural fats and oils. Enzymatic interesterification provides an important route to modify physical and nutritional properties of milkfat without generating trans isomers. This process makes use of lipases, a versatile class of enzyme that is able to perform efficiently the target modification in both solvent and solvent free systems. The present review covers important features of lipases, lipase-catalyzed interesterification reactions and their effects on the composition and texture of the resulting product.
  • Blends of PHB and its copolymers: miscibility and compatibility Revisão

    Quental, Antonio Carlos; Carvalho, Fabiana Pires de; Tada, Eduardo dos Santos; Felisberti, Maria Isabel

    Abstract in English:

    Poly(hydroxybutyrate) and its copolymers are linear polyesters behaving as conventional thermoplastic materials. However, they are totally biodegradable and produced by a wide variety of bacteria from renewable sources. Some properties and high production cost are still preventing future applications. In an attempt to improve the properties and to reduce cost blending PHB with others polymeric materials is one of the most efficient method. In this paper, miscibility, compatibility, morphological and mechanical aspects of PHB blends will be reviewed. An extensive revision over twenty last years was realized about works of blends based on PHB and its copolymers.
  • Determination of free urinary cortisol in cushing's syndrome using reversed-phase high performance liquid chromatography

    Sugawara, Eduardo Kinio; Ribeiro Neto, Luciane Maria; Verreschi, Ieda Terezinha do Nascimento

    Abstract in English:

    Determination of free urinary cortisol is a test of choice in the diagnosis of Cushing's syndrome. In this study, cortisol was quantified using reversed-phase high-performance liquid chromatography (RP-HPLC) in urine samples previously extracted with ether and using triamcinolone acetonide as internal standard (IS). A BDS-Hypersil-C18® column, water-acetonitrile (72:28; v/v), with a flow rate of 1.0 mL/min and detection at 243 nm were used. This method showed to be both effective and efficient, with sensitivity and linearity ranging from 2.50 to 150 μg/L, and can be used in substitution to the radioimmunoassay technique within this concentration range.
  • Spatial distribution of organic tin compounds in coastal sediment and Phallusia nigra of the Todos os Santos Bay and northern coast of Bahia - Brazil Nota Técnica

    Pletsch, Adelmo Lowe; Beretta, Magda; Tavares, Tania Mascarenhas

    Abstract in English:

    Organic tin compounds were investigated in the sediment of twenty-four stations located in the Todos os Santos Bay and the north coast of Bahia - Brazil. The concentration of these organic tin was also determined in a ascidium species of Phallusia nigra. The speciation and quantification was performed by GC-MS/MS. The highest concentrations were: tributyltin (TBT) 438 ng g-1, dibutyltin (DBT) 207 ng g-1, monobutyltin (MBT) 423 ng g-1, diphenyltin (DPT) 25.8 ng g-1 and monophenyltin (MPT) 55.0 ng g-1. DBT and MBT were found in Phallusia nigra, with highest concentrations of 294.1 and 148.5 ng g-1, respectively.
  • Removal of copper(II) from sugar-cane spirits employing chitosan

    Janegitz, Bruno C.; Oliveira, Andrea; Gomes, Marcos S.; Sartori, Elen R.; Pereira-Filho, Edenir R.; Fatibello-Filho, Orlando

    Abstract in English:

    A method employing chitosan as complexant agent in the removal of copper(II) ions generally present in the Brazilian cachaça samples is herein proposed. The efficiency of this method is attributed to its high capacity of metal cations adsorption, mainly due to presence of hydroxyl and amine groups that can serve as chelating sites. The removal of copper(II) ions from this alcoholic beverage was efficient employing either in column and batch system. The analysis were carried out employing the flame atomic absorption spectrometry and the remaining copper(II) concentrations in the treated cachaça were lower than LOD of FAAS technique.
  • Development of an environmentally more benign reflectometric method for the determination of metoclopramide in pharmaceutical formulations Nota Técnica

    Doretto, Keity Margareth; Gotardo, Mara Andréia; Pezza, Helena Redigolo; Pezza, Leonardo

    Abstract in English:

    A simple and more environmentally friendly method by combined spot test-diffuse reflectance spectroscopy for determining metoclopramide in pharmaceutical formulations is described. The method is based on the reaction between metoclopramide and p-dimethylaminocinnamaldehyde, in the presence of HCl, producing a colored compound (λmáx = 580 nm) on the filter paper. The linear range was from 5.65 x 10-4-6.21x10-3 mol L-1 (r = 0.999). The limit of detection was 1.27 x 10-4 mol L-1. The proposed reflectometric method was applied successfully to the determination of metoclopramide in pharmaceuticals and it was favorably compared with the Brazilian or British Pharmacopoeia methods at 95% confidence level.
  • Preconcentration strategies in capillary electrophoresis: part 2. Manipulation of the disperse/secondary velocity Nota Técnica

    Moraes, Maria de Lourdes L. de; Tavares, Marina F. M.; Pereira, Elisabete A.

    Abstract in English:

    This work describes CE preconcentration strategies based on the effect of manipulation of the disperse/secondary velocity. Introduced by Terabe et al. in 1984, micellar electrokinetic chromatography is a powerful separation approach that increases the usage of electrokinetic phenomena for the separation of nonionic compounds. The main disadvantage of MEKC is the low concentration sensitivity associated with the limited optical path length for on-capillary photometric detection and the limited volume of sample solution that can be injected. This paper compiles on-line concentration strategies for neutral analytes by sample stacking and sweeping in micellar electrokinetic chromatography.
  • Spectrophotometric olanzapine determination in pharmaceutical formulations: method development and validation Nota Técnica

    Rêgo, Jardes Figuerêdo do; Moura, Jacira Izidório de; Moita, Graziella Ciaramella

    Abstract in English:

    Spectrophotometric methods of zero order, first and second derived order had been developed for olanzapine determination in tablets using ethanol and isopropanol as solvent. The two solvents revealed to be adequate. For the three methods the calibration curve coefficient of correlation had been greater than 0.9998 with limit of detection varying from 0.068 to 0.190 mg L-1, in ethanol, and 0.026 to 0.205 mg L-1, in isopropanol. The inter-day precision was inferior to 1.1 and 1.9 mg L-1 for ethanol and isopropanol, respectively. The average recoveries varied from 98 to 101%, in ethanol and 99 to 103% in isopropanol.
  • Development of new dissolution test and HPLC-RP method for anti-parasitic ornidazole coated tablets

    Soares, Mônica Felts de La Roca; Soares Sobrinho, José Lamartine; Grangeiro Júnior, Severino; Silva, Keyla Emanuelle Ramos da; Alves, Lariza Darlene Santos; Rolim Neto, Pedro José

    Abstract in English:

    This work aimed the development and validation of a new dissolution test for ornidazole coated tablets. The dissolution conditions were determined after testing Sink conditions, dissolution medium, apparatus, stirring speed, 24 h stability and medium filtration influence. The best conditions were paddle at a stirring speed of 75 rpm and 900 mL of 0.1 M HCl. A new HPLC quantification method was developed and validated. The dissolution test and quantification method showed to be adequate for their purposes and could be applied for quality control of ornidazole coated tablets, since there is no official monograph.
  • Determination of the enthalpy of vaporization of liquid compounds by the Smith Menzies (isoteniscope) method Educação

    Gerola, Adriana Passarella; Peloi, Lilian Somenci; Hioka, Noboru; Santin Filho, Ourides; Kato, Lilian Akemi

    Abstract in English:

    This article proposes an experimental procedure to determine the enthalpy (and entropy) of vaporization of organic liquid compounds, by the Smith-Menzies (isoteniscope) method. The values of vapor pressure at different temperatures were obtained and ΔvH (and ΔvS) were graphically determined, using the Clausius-Clapeyron equation. The results for diethyl-ether, propanone, ethanol and n-hexane are in very good agreement with those from literature. A historical and thermodynamic discussion on equations that correlates vapor pressures and temperature precedes the experimental proposition.
  • Produtividade em pesquisa do CNPq: análise do perfil dos pesquisadores da Química Assuntos Gerais

    Santos, Natacha Carvalho Ferreira; Cândido, Lucilene Faustina de Oliveira; Kuppens, Cristiano Lima

    Abstract in English:

    The profile of the CNPq Research Productivity Program in Chemistry was studied using the Plataforma Lattes curricula of all researchers with grants in effect as of March 2009. Most of them are male (67.2%), working in Federal Universities (59.4%) and located in Southeastern Brazil (63.7%). There is no evident homogeneity among researchers of the same level/category concerning the productivity criterions used (the H index and the scientific productivity of the last five years). CNPq and the Chemistry Assessor Committee have been focusing on making their judgments unbiased, by using quantitative parameters, but such overlap is still noticeable.
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