• QUALIS: Quo Vadis? Editorial

    Andrade, Jailson B. de; Galembeck, Fernando
  • Estudo da adsorção de surfactante catiônico na matriz inorgânica fosfato de nióbio hidratado Artigo

    Pereira, Paulo Henrique Fernandes; Silva, Maria Lucia C. P. da

    Abstract in English:

    This work describes the study the adsorption of a cationic surfactant, cetyl trimethyl ammonium bromide (CTAB) in the hydrous niobium phosphate matrix. The matrix was characterized by powder X-ray diffraction (DRX), thermal analysis (TG), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and surface area measurements (BET). The Langmuir and Freundlich isothermal models were used in the CTAB adsorption study. The adsorption process wasn`t favorable for the NbOPO4.nH2O in both studied models.
  • Constituintes químicos de Parmotrema lichexanthonicum Eliasaro & Adler: isolamento, modificações estruturais e avaliação das atividades antibiótica e citotóxica Artigo

    Micheletti, Ana C.; Beatriz, Adilson; Lima, Dênis Pires de; Honda, Neli K.; Pessoa, Cláudia do Ó; Moraes, Manoel Odorico de; Lotufo, Letícia Veras; Magalhães, Hemerson Iury Ferreira; Carvalho, Nádia C. P.

    Abstract in English:

    From the lichen Parmotrema lichexantonicum were isolated the depsidone salazinic acid, the xanthone lichexanthone, and the depside atranorin. The two major compounds, salazinic acid and lichexanthone, were selected for structure modifications. Salazinic acid afforded O-alkyl salazinic acids, some of them potentially cytotoxic against tumor cell lines (HCT-8, SF-295 and MDA/ MB - 435). From lichexanthone were obtained norlichexanthone, 3-O-methylnorlichexanthone, 3-O-methyl-6-O-prenylnorlichexanthone, 3,6-di-O-prenyl-norlichexanthone, 3,6-bis[(3,3-dimethyloxyran-2-il)methoxy]-1-hydroxy-8-methyl-9H-xanten-9-one and 3,6-bis[3-(dimethylamine)propoxy]-1-hydroxy-8-methyl-9H-xanten-9-one. The last compound was the most active against S. aureus.
  • Um novo procedimento de síntese da zeólita A empregando argilas naturais Artigo

    Rigo, Reus T.; Pergher, Sibele B. C.; Petkowicz, Diego I.; Santos, João H. Z. dos

    Abstract in English:

    This work proposes the synthesis of zeolite A by IZA standard proceedures starting from a natural clay. The clay was used in its natural form and after calcination at 900ºC. The resulting materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and porosity analysis by nitrogen adsorption. Results showed low surface area for Na-A zeolite in sodium form, but a higher one in CaA based on the nitrogen accessibility. The presence of cubic crystals for the A phase was observed in the SEM micrographies. The new procedure starting from natural clay favors the formation of sodalite while that using the calcinated clay gives A.
  • Extração seletiva de metais pesados em sedimentos de fundo do Rio Tietê, São Paulo Artigo

    Bevilacqua, José Eduardo; Silva, Ivone Silveira da; Lichtig, Jaim; Masini, Jorge César

    Abstract in English:

    Sediment samples from Tietê river were submitted to chemical and sequential extractions of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn). It was followed a single extraction by using 0.1 mol L-1 hydrochloric acid and a sequential procedure to evaluate possible chemical associations described as exchangeable, carbonate, reducible oxides, sulfide, organic matter and residual fractions. High concentrations of heavy metals were determined at Pirapora reservoir, which is closer to the Metropolitan Area of São Paulo while for Barra Bonita reservoir, the results showed low concentrations for such elements. Acid volatile sulfides, grain size distribution and carbon contents were also determined.
  • Estudo de adsorção de compostos sulfurados utilizando um diesel comercial dopado com benzotiofeno e dibenzotiofeno Artigo

    Scherer, Robison P.; Malvesti, Álvaro L.; Pergher, Sibele B. C.; Souza, Wladmir Ferraz de

    Abstract in English:

    Desulphurization process by adsorption was studied employing a commercial diesel dooped with 1000 mg/L of benzothiophene and dibenzothiophene. The adsorbents materials employed were three types of activated alumina (acid, basic and neutral). For comparison, adsorption process was made also using oxidized diesel sample. The results showed that the adsorbents were selective for sulphur compounds removal from fuels. The contact time have influence in adsorption process achieving 80% of removal for not oxidized dibenzothiophene. The three studied alumina types showed similar behavior and a greater selective in dibenzothiophene adsorption than benzothiophene. Dibenzothiophene removal is more effective in samples not oxidized, whereas the benzothiophene was almost totally removed in oxidized sample.
  • Efeito da composição das correntes do conversor das unidades de FCC no desempenho catalítico de aditivos DESOx Artigo

    Polato, Carla Maria Salerno; Monteiro, José Luiz Fontes; Henriques, Cristiane Assumpção

    Abstract in English:

    Hydrotalcite-like compounds having Mg partially replaced by Cu or Mn were prepared and used as precursors for two mixed oxides (Cu-OM50 and Mn-OM50) that were evaluated for SOx removal in the presence of O2, NO and CO. Under SO2/O2 reaction system, SOx removal was slightly higher over Cu-OM50. The addition of CO and NO to the feed markedly hindered the SO2 oxidation over Cu-OM50 while no significant effect was observed for Mn-OM50. For the regeneration step, the use of propane instead of H2 reduces regeneration capacity, mainly for Cu-OM50. Mn-OM50 was less affected by the feed composition, suggesting that it was a promising additive for SOx removal.
  • Estudo da síntese da zeólita MCM-71 Artigo

    Luvison, Caroline; Mignoni, Marcelo L.; Pergher, Sibele B. C.

    Abstract in English:

    A new kind of material, denominated MCM-71, was synthesized and characterized by several complementary techniques: X Ray Diffractometry, textural analysis by nitrogen adsorption, Scanning electronic microscopy and infrared spectroscopy. MCM-71 zeolite was successfully synthesized by hydrothermal synthesis in the presence of triethanolamine. Mordenite phase as impurity was not detected, otherwise quartz was observed. The MCM-71 sample obtained presented a BET surface area of 20 m²/g in the as synthesized form and of 85 m²/g in protonic form. By SEM was observed crystals with rectangular shape with average size of 2 x 0,2 x 0,05 µm and this crystals were agglomerated in spherical particles with average diameter between 14 and 24 µm.
  • First secondary metabolites from Herissantia crispa L (Brizicky) and the toxicity activity against Artemia salina Leach

    Costa, Danielly Albuquerque da; Matias, Wemerson Neves; Lima, Igara Oliveira; Xavier, Aline Lira; Costa, Vivian Bruna Machado; Diniz, Margareth de Fátima Formiga Melo; Agra, Maria de Fátima; Batista, Leônia Maria; Souza, Maria de Fátima Vanderlei de; Silva, Davi Antas e

    Abstract in English:

    The phytochemical investigation of Herissantia crispa led to the isolation of seven compounds, identified as: sitosterol 3-O-β-D-glucopyranoside, stigmasterol 3-O-β-D-glucopyranoside, 3,5,7,4'-tetrahydroxyflavone (kaempferol), 3,5,7,3',4'-pentahydroxyflavone (quercetin), unpublished in the genus Herissantia, besides β-sitosterol, kaempferol 3-O-β-D-(6''-E-p-coumaroil) (tiliroside) glucopyranoside and kaempferol 3,7-di-O-α-L-ramnopyranoside (lespedin), described for the first time in the species. The structural determination of the compounds was made by means of spectroscopy methods such as Infrared Spectroscopy, ¹H and 13C Nuclear Magnetic Resonance, with the aid of two dimensional techniques, and by comparison with literature data. The toxicity activity of the MeOH extract and lespedin on Artemia salina Leach. was also carried out.
  • The role of bound chlorine in the brightness reversion of bleached hardwood kraft pulp

    Eiras, Kátia Maria Morais; Colodette, Jorge Luiz; Silva, Vanessa Lopes

    Abstract in English:

    Our previous paper showed fragmentary evidence that pulp brightness reversion may be negatively affected by its organically bound chlorine (OX) content. A thorough investigation on eucalyptus kraft pulp led to the conclusion that OX increases reversion of certain pulps but this trend is not universal. Alkaline bleaching stages decrease reversion regardless of pulp OX content. Pulps bleached with high temperature chlorine dioxide revert less than those bleached with conventional chlorine dioxide in sequences ending with a chlorine dioxide stage but similarly in sequences ending with a final peroxide stage. The use of secondary condensate for pulp washing decreases reversion.
  • Determinação de benzeno, tolueno, etilbenzeno e xilenos em gasolina comercializada nos postos do estado do Piauí Artigo

    Silva, Flamys Lena do N.; Santos Jr., José Ribeiro dos; Moita Neto, José Machado; Silva, Rosa Lina G. do N. P. da; Flumignan, Danilo Luiz; Oliveira, José Eduardo de

    Abstract in English:

    Automotive gasoline consists of a complex mixture of flammable and volatile hydrocarbons derived from crude oil with carbon numbers within the range of 4-12 and boiling points range of 30-225 ºC. Its composition varies with the kind of crude oil and the type of refinery process that they undergone. Aromatics hydrocarbons, in particular benzene, toluene, ethylbenzene and isomeric xylenes (BTEX) are the toxic group constituents presents. GC-FID was employed to quantify these hydrocarbons in 50 commercial gasoline samples from Piauí state. Statistical analysis techniques, such as PCA and HCA were used to analyze the data. Moreover, several validation parameters were evaluated.
  • Hidrolisado protéico de pescado obtido por vias química e enzimática a partir de corvina (Micropogonias furnieri) Artigo

    Martins, Vilásia Guimarães; Costa, Jorge Alberto Vieira; Prentice-Hernández, Carlos

    Abstract in English:

    The fish proteins has the advantage of a high sensibility to the hydrolysis and also a balanced composition in aminoacids. The production of protein hydrolyzed from by-products of fish process industry has been receiving more attention on the last years. The aim of this work was to evaluate the production of protein hydrolyzed from Micropogonias furnieri through chemical and enzymatic methods, verifying some functional properties. The results showed that the production of the hydrolyzed improved some functional properties of the proteins found in the filet and in the waste, what is desirable for a subsequent application.
  • Degradação fotoeletroquímica de corantes dispersos em efluente têxtil utilizando fotoanodos de Ti/TiO2 Artigo

    Brunelli, Tamara F. T.; Guaraldo, Thaís T.; Paschoal, Fabiana M. M.; Zanoni, Maria Valnice B.

    Abstract in English:

    The degradation of disperses dyes in aqueous solution and in effluents from textile industry has been investigated by photoelectrocatalytic oxidation using nanoporous thin films electrodes of Ti/TiO2. Samples of dispersil black dye and dispersil blue dye after 300 min of photoelectrolyzed at applied potential of +1.0 V and UV irradiation exhibited 100% of discoloration and 90% and 64% reduction total organic carbon, respectively. The proposed method was applied with success in a textile industry effluent containing residues of these dyes, which after 300 min of treatment leads to reduction of 60% of COD and 64% removal of TOC.
  • Otimização dos parâmetros de produção de hidrolisados protéicos enzimáticos utilizando pescado de baixo valor comercial Artigo

    Santos, Sarita D´Avila dos; Martins, Vilásia Guimarães; Salas-Mellado, Myriam; Prentice-Hernández, Carlos

    Abstract in English:

    The enzymatic modification of proteins has been widely studied with the aim of add value to low commercial value fish. The objective of this work was to evaluate and optimize the parameters involved in the production process of an enzymatic protein hydrolyzed with high protein content. The results showed that for Alcalase the most significant parameters were temperature, pH and substrate concentration and for Flavourzyme were pH, substrate concentration and enzyme concentration. It was obtained for Alcalase a predictive model for the recovered nitrogen and for Flavourzyme a predictive model for the hydrolysis degree.
  • Antimicrobial and antileishmanial activity of essential oil from the leaves of Annona foetida (Annonaceae)

    Costa, Emmanoel Vilaça; Pinheiro, Maria Lúcia Belém; Silva, Jefferson Rocha de Andrade; Maia, Beatriz Helena Lameiro de Noronha Sales; Duarte, Marta Cristina Teixeira; Amaral, Ana Cláudia Fernandes; Machado, Gérzia Maria de Carvalho; Leon, Leonor Laura

    Abstract in English:

    bicyclogermacrene (35.12%), (E)-caryophyllene (14.19%) and α-copaene (8.19%). The antimicrobial and antileishmanial activities were investigated. The oil showed potent antimicrobial activity against Candida albicans and Rhodococcus equi. The oil also showed significant antileishmanial activity, giving the best results against Leishmania guyanensis. A preliminary cytotoxicity assay for this oil was carried out on hamster and mice (Balb/c) peritoneal macrophages. The results obtained were similar to pentamidine and considered not to be cytotoxic to macrophages.
  • Caracterização de cinza do bagaço de cana-de-açúcar para emprego como pozolana em materiais cimentícios Artigo

    Cordeiro, Guilherme Chagas; Toledo Filho, Romildo Dias; Fairbairn, Eduardo de Moraes Rego

    Abstract in English:

    This work presents the results of morphological and physical-chemical characteristics of a sugar cane bagasse ash material sample produced under controlled burning conditions. The investigation was carried out by analyzing chemical composition, X-ray diffraction, 29Si nuclear magnetic resonance, morphology, thermal analysis, particle size, specific surface, and density. Moreover, the pozzolanic activity of the ash was evaluated by pozzolanic activity index and Chapelle's method. The results suggest that the sugar cane bagasse ash has adequate properties to be used as pozzolan in construction materials.
  • Optimization of methodology to analyze ascorbic and dehydroascorbic acid in vegetables

    Campos, Flávia Milagres; Ribeiro, Sônia Machado Rocha; Della Lucia, Ceres M.; Pinheiro-Sant'Ana, Helena Maria; Stringheta, Paulo César

    Abstract in English:

    In this study, different solutions to extract vitamin C were tested. High-performance liquid chromatography was chosen and the conditions were based on isocratic elution in reverse phase column. Dehydroascorbic acid was determined indirectly after its reduction using dithiothreitol. The use of metaphosphoric acid to stabilize the vitamin C was shown to be required and it was necessary to neutralize the pH of the extract to apply dithiothreitol. The average recovery was 90% in collard and tomato samples. The presence of oil did not interfere in extraction and the methodology can be used to analyze stir fried vegetables.
  • Análise de resíduos de agrotóxicos em tomates empregando dispersão da matriz em fase sólida (DMFS) e cromatografia gasosa Artigo

    Pinho, Gevany P.; Neves, Antônio A.; Queiroz, Maria Eliana L. R.

    Abstract in English:

    This work was aimed on optimization of the matrix solid-phase dispersion (MSPD) technique using gas chromatography for analyzing residues of chlorpyriphos, λ-cyhalothrin, cypermethrin and deltamethrin in tomatoes. The results showed that silica was more efficient for the clean up of extracts, but florisil provided the highest recovery rates. A 2³ complete factorial design was carried out to evaluate the absorbent/sample ratio, presence of co-column (silica) and ultrasonic bath on the extraction rate. The percentage of extraction of the pesticides chlorpyriphos, λ-cyhalothrin, cypermethrin and deltamethrin were 64.7, 88.3, 99.2 and 89.2%, respectively, with relative standard deviations below 5%.
  • Adsorção e dessorção aniônicas individuais por gibbsita pedogenética Artigo

    Pozza, Adélia A. A.; Curi, Nilton; Guilherme, Luiz R. G.; Marques, João J. G. S. M.; Costa, Enio T. S.; Zuliani, Daniela Q.; Motta, Paulo E. F.; Martins, Rodrigo S.; Oliveira, Luiz C. A.

    Abstract in English:

    Anion adsorption/desorption dynamics was studied as individual processes on surface of particles of a gibbsitic clay. The data suggest a remarkable gibbsite role as nitrate leaching retardant in soil. The opposite behavior of gibbsite towards adsorption/desorption of silicate and phosphate suggests the need of an adequate compromise solution regarding interval and rate applications of anions in cultivated gibbsitic soils. The high P adsorption verified in pH values lower than that reported for the point of zero charge of synthetic Al-hydroxides implies that this process takes place in pedogenic gibbsites through inner sphere complexation.
  • Avaliação da estabilidade oxidativa de biodiesel de óleo de girassol com antioxidantes Artigo

    Ferrari, Roseli Aparecida; Souza, Waleska Lemes de

    Abstract in English:

    Biodiesel can contain unsaturated fatty acids, which are susceptible to oxidation, being able to change into polymerized compounds. In this work biodiesel was characterized according to physical-chemistry parameters and the antioxidant activity of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ) added to biofuel was analyzed. Biodiesel was submitted to accelerate oxidation in the Schaal oven test, and peroxide value was analyzed.The absorptivity values at 232 nm and 270 nm and oxidative stability in Rancimat®were determined. It was observed that TBHQ presented superior antioxidant activity than BHT and BHA.
  • Determinação espectrofotométrica em fluxo de cloro em água usando célula de longo caminho óptico e multicomutação Artigo

    Salami, Fernanda Helena; Bonifácio, Viviane Gomes; Fatibello-Filho, Orlando; Marcolino-Jr, Luiz Humberto

    Abstract in English:

    A multicommuted method for determination of chlorine in water samples using a 100-cm cell was developed. In this method, orto-Tolidine reacts with chlorine and the product was monitored at 438 nm. The analytical curve for chlorine was linear in concentration range from 1.34x10-6 to 2.01x10-5 mol L-1 with a detection limit of 9.40x10-8 mol L-1. A sampling rate of 45 h-1and a RSD of 1.0 % (n = 15) were obtained. The method was applied with success for chlorine determination in six water samples.
  • Teores de carbamato de etila em aguardentes de cana e mandioca: parte II Artigo

    Andrade Sobrinho, Luiz Gualberto de; Cappelini, Luciana Tereza Dias; Silva, Alexandre Ataíde da; Galinaro, Carlos Alexandre; Buchviser, Silmara França; Cardoso, Daniel Rodrigues; Franco, Douglas Wagner

    Abstract in English:

    Herein, we report the concentration of ethyl carbamate (EC) and copper in 380 samples of sugar-cane spirit and 45 samples of manioc spirit as determined by GC-MS and FAAS respectively. The cyanide content determined spectrophotometrically is reported for the manioc spirit. Sugar cane spirit produced by alembic distillation (70,0 µg L-1) shown a lower content of EC than samples produced by column distillation (270 µg L-1). No simple correlation between the content of EC and copper for sugar cane spirit as well among the concentration of EC, copper, and cyanide for manioc spirit could be observed.
  • Adsorção competitiva de inibidor de corrosão usado em poços de perfuração de petróleo sobre aço, esmectita e arenito Artigo

    Souza, Ingrid A. G. A.; Petri, Denise F. S.; Queiroz Neto, João C.

    Abstract in English:

    A commercial corrosion inhibitor used in petroleum production was characterized by means of infrared spectroscopy and energy dispersive spectroscopy (EDS). Predicting the adsorption behavior of corrosion inhibitor onto steel, sandstone and esmectite is the key to improve working conditions. In this study, the adsorption kinetics of inhibitor formulations in HCl 15% or in Mud Acid (HCl 13,5% and ammonium bifluoride) onto steel, sandstone and esmectite was determined by means of spectrophotometry. Kinetic parameters indicated that adsorption of inhibitor in the presence of bifluoride was favored. Moreover, the adsorption constant rate was the largest when the substrate was esmectite.
  • Estudo da degradação de ranitidina via H2O2 eletrogerado/Fenton em um reator eletroquímico com eletrodos de difusão gasosa Artigo

    Beati, André A. G. F.; Rocha, Robson S.; Oliveira, Joaquim G.; Lanza, Marcos R. V.

    Abstract in English:

    The study of the electrochemical degradation of the ranitidine was developed using an electrochemical reactor with a gas diffusion electrode (GDE) as cathode. The electrolysis experiments was performed at constant current (1 < A < 10) and flow rate of 200 L h-1. The process of drug degradation, chemical/electrochemical and electro-Fenton ways, using electrochemical reactor showed best efficiency at current values of > 4 A. The process reached a production of 630 mg L-1 of the H2O2 at 7 A. The ranitidine concentrations was reduced in 99.9% (HPLC) and chemical oxygen demand (COD) was reduced in 86.7% by electro-Fenton.
  • Estudo fitoquímico das cascas das raízes de Zanthoxylum rigidum Humb. & Bonpl. ex Willd (Rutaceae) Artigo

    Moccelini, Sally Katiuce; Silva, Virgínia Claudia da; Ndiaye, Eliane Augusto; Sousa Jr., Paulo Teixeira de; Vieira, Paulo Cezar

    Abstract in English:

    Chemical investigation from root barks of Z. rigidum, resulted in the isolation of lupeol, a mixture of steroids campesterol, sitosterol, stigmasterol, sacarose, hesperidin, N-methylatanine and 6-acetonyldihydrochelerythrine. Their structures were established by spectral data analysis. No previous work has been reported on Z. rigidum species.
  • Caracterização de escamas do peixe piau (Leporinus elongatus) e sua aplicação na remoção de Cu(II) de meio aquoso Artigo

    Santos, Elias de Barros; Vieira, Eunice Fragoso da Silva; Cestari, Antonio Reinaldo; Barreto, Ledjane Silva

    Abstract in English:

    Characterization of fish scales of Leporinus elongatus and their application in the removal of Cu(II) from aqueous solutions are described. It was observed that the scales are mainly formed by hydroxyapatite and type I collagen. Adsorption of Cu(II) was performed using batch experiments at 25 0C. The ANOVA statistical results have shown that the Langmuir model was successful applied to determine the maximum adsorption capacity of 2.686 x10-4 mol g-1 and the Langmuir equilibrium parameter (b) of 168.8 L mol-1. The Langmuir separation parameter, R L, has shown favorable adsorption of Cu(II) on the scales.
  • Ácidos ciclopentênicos do óleo da sapucainha (Carpotroche brasiliensis Endl, Flacourtiaceae): o primeiro antileprótico usado no Brasil Artigo

    Oliveira, Adriana S.; Lima, Josélia A.; Rezende, Claudia M.; Pinto, Angelo C.

    Abstract in English:

    The chaoolmugra oil is one of the oldest medicines used for leprosy until the development of sulfas. In Brazil, it is known as sapucainha oil that is obtained from Carpotroche brasilienesis seeds (Flacourtiaceae). Chemical and medicinal studies of sapucainha oil were introduced in Brazil by Peckolt, Cole and Cardoso which showed that major ciclopentenyl fatty acids as chaulmoogric, hydnocarpic and gorlic were responsible for its bactericidal activity. In this work, a method for quantification of sapucainha oil acidic fraction by HRGC was established using methyl n-heptadecanoate as internal standard. The oil chemical stability was investigated by the use of GC-MS, IR, ¹H and 13C NMR and showed that the main degradation products belong to the cyclopentenyl moiety oxidation.
  • Processos físico-químicos em drenagem ácida de mina em mineração de carvão no sul do Brasil Artigo

    Campaner, Veridiana Polvani; Luiz-Silva, Wanilson

    Abstract in English:

    Acid mine drainage generated from coal mine showed a pH of 3.2, high concentrations of SO4(2-), Al, Fe, Mn, Zn and minor As, Cd, Co, Cr, Cu, Ni and Pb. The major reduction in the concentration occurred for Al, As, Cr, Fe and Pb after the treatment with CaO. The evolution of these acid waters within the tributary stream showed decreasing concentration for all soluble constituents, except Al. This natural attenuation was controlled by pH (6.4 to 10.8) as a result of concurrent mixing with tributary stream and reaction with local bedrock that contains limestone. Aluminum increasing concentration during this evolution seems to be related to an input of Al-enriched waters due to the leaching of silicate minerals in alkaline conditions.
  • Highly selective transport of mercury(II) ion through a bulk liquid membrane

    Shokrollahi, Ardeshir; Ghaedi, Mehrorang; Shamsipur, Mojtaba

    Abstract in English:

    In this work carrier-facilitated transport of mercury(II) against its concentration gradient from aqueous 0.04 M hydrochloric acid solution across a liquid membrane containing isopropyl 2-[(isopropoxycarbothiolyl)disulfanyl]ethane thioate (IIDE) as the mobile carrier in chloroform has been investigated. Sodium thiocyanate solution (1.6 M) was the most efficient receiving phase agent among several aqueous reagents tested. Various parameters such as investigated. Under optimum conditions the transport of Hg(II) across the liquid membrane is more than 97% after 2.5 h. The carrier, IIDE, selectively and efficiently could able to transport Hg (II) ions in the presence of other associated metal ions in binary systems.
  • Efeito do tratamento térmico na microestrutura, turbostraticidade e superfície de carbono vítreo reticulado analisado por XPS, espalhamento Raman e voltametria cíclica Artigo

    Gonçalves, Emerson Sarmento; Rezende, Mirabel Cerqueira; Baldan, Maurício Ribeiro; Ferreira, Neidenêi Gomes

    Abstract in English:

    The structural and surface properties of reticulated vitreous carbon (RVC) were discussed as a function of its heat treatment temperature (HTT), for samples produced in the range from 700 to 2000 ºC, using the furfuryl precursor resin. The samples were analyzed by x-ray photoelectron spectroscopy, first and second order Raman scattering as well as electrochemical response. Exploring the material turbostraticity concept, the interdependence between the RVC chemical surface variation and its defects were demonstrated. The influence of heteroatom presence was discussed in the material ordering for HTT lower than 1300 ºC while the graphitization process evolution was also pointed out for HTT higher than 1500 ºC.
  • Desenvolvimento e validação de um método analítico rápido por cromatografia líquida de alta eficiência para determinação de nimesulida em estudos de liberação in vitro Artigo

    Ruela, André Luís Morais; Araújo, Magali Benjamim; Pereira, Gislaine Ribeiro

    Abstract in English:

    A high performance liquid chromatography (HPLC) method has been developed for a rapid determination of nimesulide in dissolution studies. Nimesulide was analyzed using 5 µm Lichrospher® RP-18 column (125 x 4 mm i.d.) and mobile phase acetonitrile: phosphate buffer pH=6.0 (55:45) at a flow-rate of 1.0 mL min-1. Detection was carried out at 300 nm at 25 ºC. The method was applied to analysis of nimesulide in in vitro release studies and showed a rapid and efficient analytical alternative for evaluation of dissolution profile of nimesulide.
  • Importance of the lipid peroxidation biomarkers and methodological aspects FOR malondialdehyde quantification

    Grotto, Denise; Maria, Lucas Santa; Valentini, Juliana; Paniz, Clóvis; Schmitt, Gabriela; Garcia, Solange Cristina; Pomblum, Valdeci Juarez; Rocha, João Batista T.; Farina, Marcelo

    Abstract in English:

    Free radicals induce lipid peroxidation, playing an important role in pathological processes. The injury mediated by free radicals can be measured by conjugated dienes, malondialdehyde, 4-hydroxynonenal, and others. However, malondialdehyde has been pointed out as the main product to evaluate lipid peroxidation. Most assays determine malondialdehyde by its reaction with thiobarbituric acid, which can be measured by indirect (spectrometry) and direct methodologies (chromatography). Though there is some controversy among the methodologies, the selective HPLC-based assays provide a more reliable lipid peroxidation measure. This review describes significant aspects about MDA determination, its importance in pathologies and biological samples treatment.
  • Imobilização de enzimas em suportes cromatográficos: uma ferramenta na busca por substâncias bioativas Revisão

    Cardoso, Carmen Lúcia; Moraes, Marcela C. de; Cass, Quezia B.

    Abstract in English:

    The development and characterization of bioreactors or IMER (immobilized enzyme reactors) as research tools are important in the scope of medicinal chemistry and constitute an alternative for the rational development of drugs. This approach does not require highly purified enzymes or a great amount of protein, but increase the enzymatic stability against heat, organic solvents and pH, without too much loss of catalyst activity. Immobilized enzyme reactors (IMER) can be used for the accomplishment of high efficiency screening on-line and, thus inhibitors can be quickly identified. Here, we emphasize the development of IMER by use of different methods of immobilization and chromatographic supports. Their applications, in different areas of research, are also fully discussed.
  • Degradação de fármacos residuais por processos oxidativos avançados Revisão

    Melo, Silene Alessandra Santos; Trovó, Alam Gustavo; Bautitz, Ivonete Rossi; Nogueira, Raquel Fernandes Pupo

    Abstract in English:

    The concern about aquatic ecosystems and the potential risk of drinking water contamination by pharmaceuticals have stimulated the study of processes for the efficient degradation of these contaminants, since the conventional treatment have been inefficient on that purpose. The advanced oxidation processes (AOPs) appear as viable alternatives due to their efficiency on the degradation of different classes of organic contaminants. This review presents an overview of the main AOP (O3, H2O2/UV, TiO2/UV, Fenton and photo-Fenton) which have been applied to the degradation of different pharmaceuticals. The main results obtained, intermediates identified and toxicity data are presented.
  • Exudados de la raiz y su relevancia actual en las interacciones alelopaticas

    Oliveros-Bastidas, Alberto de J.; Macías, Francisco A.; Fernández, Ceferino Carrera; Marín, David; Molinillo, José M. G.

    Abstract in English:

    Detrimental interactions among plants are expressed by competition for nutrients, chemical interferences and/or parasitism. Root exudates have an enormous potential at the modulation of these three mechanisms. These exudates play a key role as "phytoalexins release routes", being the allelochemicals, which regulate the chemical interactions, an example. This review presents the most recent findings on the currently used methodologies for the study of the exudation phenomenon. The methodologies for the sampling and analysis of such chemicals, as well as all other factors considered to increase the production of root exudates, are also examined.
  • O estado da arte da cromatografia líquida de ultra eficiência Revisão

    Maldaner, Liane; Jardim, Isabel Cristina Sales Fontes

    Abstract in English:

    Ultra Performance Liquid Chromatography (UPLC) retains the same principles as High Performance Liquid Chromatography (HPLC), but uses 1-2.1 mm i.d. columns with sub-2 µm particles. It is considered the newest advance in analytical separation science. The use of these small particles with mobile phases at high linear velocities increases resolution and detectability and decreases analysis time. Thus, the analyses are faster, the solvent volume is smaller, the efficiency is higher and the detectability is 2-3 times higher when compared with HPLC analysis.
  • Medidas de tensão superficial pelo método de contagem de gotas: descrição do método e experimentos com tensoativos não-iônicos etoxilados Nota técnica

    Teixeira Neto, Érico; Malta, Marcos Maziero; Santos, Ronaldo Gonçalves dos

    Abstract in English:

    Surface tension knowledge of surfactants aqueous solutions is important during amphiphilic molecule manufacturing and new product development, as feedback information to handle synthesis parameters to target performance. Drop counting method is an interesting simplification of drop weight method for surface tension measurements. A simple laboratory measurement device, with capability for temperature control, was assembled to allow investigation of ethoxylated surfactants. The implementation of the method was preceded by a detailed investigation of two factors that may affect the measured surface tension: drop formation velocity and surfactant ethoxylation degree. The limitations of the method are discussed on this basis.
  • Estudo do comportamento eletroquímico de substâncias complexantes utilizando eletrodo de cobre Nota técnica

    Coutinho, Cláudia F. B.; Coutinho, Lincoln F. M.; Mazo, Luiz H.

    Abstract in English:

    Copper electrode can be used for determination of complexing compounds through complexation reactions between Cu(II) and the analites. In this work some studies with three compounds were performed: glycine (precursor of glyphosate synthesis), herbicide glyphosate and aminomethylphosphonic acid (main metabolite of glyphosate). These compounds are complexing agents for Cu electrodes. Through simple experiments (cyclic voltammetry and corrosion studies) the applicability of the copper electrode as electrochemical sensor for complexing compounds in flow systems was presented.
  • Construção de um sistema simples e compacto de recirculação d'água sob pressão para trompa d'água Nota técnica

    Imbroisi, Dennis de Oliveira; Santana, Carmen Silvia Tavares de; Araújo, Cleônia Roberta Melo; Silva, Wilson Ceciliano da; Lopes, Cleylton Bezerra

    Abstract in English:

    Vacuum pumps are very useful in physical, chemical and biological experiments. In this communication it is described the design of a compact and low cost water recirculating system employing a water-jet aspirator pump as the vacuum source. The system requires only a water pump, water-jet aspirator pump, commercial PVC water tubes and a drain connection.
  • A formação em Química discutida com base nos modelos proposto por estudantes de pós-graduação para o fenômeno de dissolução Educação

    Souza, Karina Aparecida de Freitas Dias de; Cardoso, Arnaldo Alves

    Abstract in English:

    Mental models play an important role in the evolution of an individual's so-called knowledge. Using such representations, students can explain, foresee, and attribute causality to observed phenomena. In the case of Chemistry, the ability to work mentally with models assumes great importance, due to the microscopic component that is characteristic of this science. With the objective of exploring students' ability to work with models, 27 students of the Chemistry Institute of UNESP were asked to describe the mechanisms of dissolution, in water, of NaCl, HCl and HCN, as well as the partial dissolution of I2. Due to difficulties of access to complex descriptors of these processes, each student was asked to explain the phenomena using words and drawings. The results of these investigations were analyzed, and enabled construction of a framework representing the Chemistry students' theoretical training, especially with respect to their most important transferred skill: an ability to model the physical world.
  • Cloração do anisol, tolueno e nitrobenzeno com ácido tricloroisocianúrico (ATCI): aspectos computacionais sobre a reatividade e regiosseletividade Educação

    Vasconcellos, Mário L. A. A.; Lima Junior, Cláudio G.

    Abstract in English:

    We present in this educational article a theoretical analysis based on DFT/B3LYP 6-311++G (d,p) and ab initio MP2/6-311++G(d,p) computational calculation about the reactivity and the regioselectivity on the chlorination reaction of anisole, toluene and nitrobenzene, using trichloroisocyanuric acid (TICA) as donor of Cl+. The H.O.M.O. / L.U.M.O. energy and N.B.O. atomic charges of various aromatic systems were calculated in ab initio level. The energies of the reagents and intermediaries were calculated using D.F.T.. These results have been presented as a quantitative example for the S E A mechanism, in the undergraduate organic chemistry disciplines.
  • Avaliação de uma proposta contextualizada sobre o ensino de polarimetria nos cursos de farmácia e engenharia de alimentos, na Universidade Federal do Ceará Educação

    Rodrigues, Deyvison Henrique da Silva; Oliveira, Alcineia Conceição

    Abstract in English:

    This work deals with an evaluation of an experimental application about polarimetry for pharmacy and food engineering courses. Foods obtained from the undergraduate students were used for demonstrating multidisciplinary concepts and these concepts were associated to the teaching of polarimetry. According to the results, the benefits of the contextualization are beyond the class and the undergraduating students became interested in control of quality of foods. From these results, it can be concluded that the experimental emphasis given is valid and creates motivation and interest for learning physico-chemistry, in comparison with the traditional methodology applied to teach polarimetry.
  • Estrategias en el desarrollo de métodos analíticos para la determinación simultánea de compuestos orgánicos por espectrofotometría derivada

    Toral, M. Inés; Orellana, Sandra; Saldías, Marta; Soto, César

    Abstract in English:

    In this work is proposed, a simple experiment for the simultaneous determination of losartan (L) and hydrochlorothiazide (H) in synthetic and real samples by derivative spectrophotometry technique. For the students it is relevant to know this technique for simultaneous determinations of drugs, allowing that the students recognize that this technique is simple, rapid and applicable to quality control. This experimental work, it is proposed in order to being applied to undergraduates into laboratories of analytical chemistry. Furthermore, it is given the integration of the theoretical knowledge with the experimental work; this correlation is of interest for the students.
  • Raios-x: fascinação, medo e ciência Assuntos gerais

    Lima, Rodrigo da Silva; Afonso, Júlio Carlos; Pimentel, Luiz Cláudio Ferreira

    Abstract in English:

    This work presents the discovery and the use of x-rays at the end of the XIXth and the beginning of the XXth century. X-rays greatly impacted science and everyday life. Their existence broke the idea that knowledge had reached a limiting step. In general, people regarded x-rays as a marvel of science, but reactions against their use were also found. Several applications were proposed, especially in medicine. However, little or no attention was paid to security measures, leading to health damages and even death. The development of the radiological protection took into account the accidents with the x-rays.
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