Programa de Pós-graduação em Química

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Aproveitamento de rejeitos da indústria de atomatados para a produção e caracterização de extratos ricos em licopeno, β-Caroteno e Vitamina E
(Universidade Federal de Goiás, 2006-03-17) SILVA, Fernanda Dias; ANTONIOSI FILHO, Nelson Roberto; http://lattes.cnpq.br/5982964870999454
The production of industrial foods derived from tomato generates high levels of rejects that are composed basically of seeds and tomato peels. This reject it is rich in carotenoids, especially lycopene and β-carotene, which are pigments whose ingestion is directly linked to the decrease of the risk of chronic-degenerative diseases. The present study has as objective develops simplified and efficient extraction and analysis methods of lycopene and β-carotene starting from this reject using palm oil as coadjutant, seeking the subsequent use of this extract for enrichment of products of easy access to classes economically inferior of the population and as a vehicle of medicines. Initially it was developed the chromatographic analysis method for three columns of RP-HPLC: C18 Chromolith SpeedROD (50 mm x 4,6 mm), C18 Nova-Pack (300 mm x 3,9 mm x 4 µm) and C30 YMC Carotenoid (250 mm x 4,6 mm x 5 µm). All the columns present a considerable reduction in the time of analysis and efficient separation between lycopene and β-carotene, when compared to the analysis reported on scientific literature. Later it was done a study of the thermal stability of the pigments by means of TG, DSC and RP-HPLC seeking to evaluate the maximum temperature which the reject can be heated without the occurrence of considerable losses of the pigments. The thermogravimetric curves demonstrated that the loss of mass happens to temperatures higher than those observed by the degradations of the pigments by RP-HPLC. It means that occurs the transformation of lycopene and β-carotene in intermediary compounds which are volatilized in higher temperatures. For the development of the extraction method several variables were tested being obtained the following optimized condition: 25 g of sample was dissolved in 50 mL of hexane and 0.1 mL of palm oil, shaking by 90 minutes under 50ºC. The proposed method demonstrated to be viable once it happens in only one stage, with the use of only an solvent which can be used again after the process. The time of extraction is completely acceptable, as well as the amount of solvent used, being all the parameters compatible with industrial implementation. The oily extract was still characterized with regard to the tocopherols and tocotrienols levels in the palm oil as well as the fatty acid and triacylglicerol compositions. It was obtained the prevalence of y-tocotrienol, oleic and palmitic acids and POO and POP triacylglicerides.
Grupo de estudo de professores de química em Barra do Garças (MT) : uma investigação-ação
(Universidade Federal de Goiás, 2007-03-31) SOUSA, Demétrio de Abreu; BOTTER JÚNIOR, Wilson; lattes.cnpq.br/6176798892327803
Composição e variabilidade química dos óleos essenciais das folhas e frutos de Eugenia dysenterica
(Universidade Federal de Goiás, 2008) Duarte, Alessandra Rodrigues; Ferri, Pedro Henrique; http://lattes.cnpq.br/2129799749473005
The chemical variations in the essential oil compositions of the wild and cultivated Eugenia dysenterica DC. (Myrtaceae) populations indicated the presence of two clusters of oils according to sampling origin. The cluster I included cultivate (subcluster IA) and mainly wild samples (subcluster IB) originating from Senador Canedo (SC), with high percentages of a-pinene (9.0 ± 2.3%), b-pinene (9.3 ± 2.6%), (Z)-b-ocimene (5.9 ± 4.2%) and g-cadinene (27 ± 5%), limonene (12 ± 9%), and caryophyllene oxide (7.4 ± 4.7%), respectively. In cluster II, with wild and cultivated samples originating from Campo Alegre de Goiás, the major constituents were b-caryophyllene (24 ± 8%), d-cadinene (13 ± 4%), and a-copaene (9.6 ± 3.2%). The canonical correlation analysis revealed that limonene, ?-cadinene, caryophyllene oxide, Zn, Cu, Fe, Mn, and mean monthly values of temperature and precipitation were quite strongly related to SC wild samples (subcluster IB), whereas (Z)-b-ocimene, a-copaene, b- caryophyllene, a-humulene, d-cadinene, and P were related to wild samples from CA and cultivated samples, regardless of population origin (subcluster IA and cluster II). Sesquiterpene hydrocarbons predominated in all population sampled and the observed essential oil chemovariation might be genetically determined (chemotypes), in addition to a clear environmental influence on the samples originating from SC site (ecotypes). Chemical variations in essential oil compositions of cultivated E. dysenterica populations in dry and wet seasons have indicated the presence of two oil clusters related to sampling origin and seasons. Cluster I included dry (subcluster IA) and mainly wet samples (subcluster IB) originating from Senador Canedo (SC), with high percentages of b-pinene?(9.3 ± 2.6%), a-pinene (9.0 ± x 2.3%), (Z)-b-ocimene (5.9 ± 4.2%) and g-cadinene (17 ± 11%), limonene (14 ± 9%), and b-pinene?(8.6 ± 5.4%), respectively. In cluster II, which included dry and wet cultivated samples originating from Campo Alegre de Goiás, the major constituents were b-caryophyllene (32 ± 15%), d-cadinene (13 ± 6%), and a- copaene (8.1 ± 4.0%). Here also, sesquiterpene hydrocarbons predominated in all the sampled populations and the observed essential oil chemovariation might be genetically determined, in addition to a clear seasonal influence only on the samples originating from the SC site. In addition, the oils from wild E. fruits harvested during three stages of ripening showed the monoterpene hydrocarbons as most abundant group of volatiles, accounting for about 68% of the total identified compounds. Limonene (25.8% and 24.6%), (E)-b-ocimene (20.3% and 21.7%) and b-pinene (12.0% and 14.2%) were the compounds in the unripe and semi-ripe stages, respectively, while g-muurolene (25.8%), b-caryophyllene (18.4%) and a- humulene (15.4%) became the major compounds in ripe fruits. The concentration of monoterpenes was high in the unripe and semi-ripe stages and decreased afterwards, while sesquiterpenes were intensively synthesized only in the last part of the ripening process.
Aplicação de métodos quimiométricos em estudos de bioequivalência do antibiótico amoxicilina
(Universidade Federal de Goiás, 2008-02-28) Ramos, Douglas Rodrigues; Souza, Paulo Sérgio de; http://lattes.cnpq.br/0834231763464061; Souza, Paulo Sérgio de; Garrote, Clévia Ferreira Duarte; Coelho, Clarimar José
The generic medicines have brought to the national population a higher possibility to access the treatment with medication, the competition stimulation and the medicine exchange insertion, in which the reference formulation can be substituted by the generic medicine, without any harm to the treatment. ANVISA (National Agency of Sanitary Surveillance) regulates this national market, demanding the bioequivalence confirmation between test and reference medicines. Therefore, in a period of six years, those studies have been performed and several generic medicines have been liberated to commercialization. However, the exchange confirmation among the several generic and reference medication are still difficult to observe due to the complexity of the values obtained. The chemometrics analysis decreases the sample space of the complex data which allows samples similarity observation as well as their classification in distinct groups. For that, Principal Components Analysis (PCA) and the Hierarchical Cluster Analysis (HCA) have been used. With these techniques an n-dimension space statistics have been evaluated for a bi-dimension of six amoxicillin bioequivalence studies as capsules and suspensions and therefore, classified them in groups in accordance with the similarity of the formulations pharmacokinetic profiles, which has allowed the medicine exchange observation. The chemometrics applications in pharmacokinetic data differentiated the pharmaceuticals forms capsule and suspensions, of absorption and elimination parameters allowing the exchange avaliations of formulations showing been useful in research laboratories or by regulatories agency for the quality monitoring of the medicine.
Encapsulação da genisteína em lipossomas: caracterização das interações farmacolipídeo, estabilidade e atividade antioxidante
(Universidade Federal de Goiás, 2008-04-28) RIBEIRO, Lidiane Radoll; LIMA, Eliana Martins; http://lattes.cnpq.br/7248774319455970
Genistein is the most abundant isoflavone, displaying the largest number of biological activities. Most studies on genistein have been based on its antioxidant, estrogenic, tyrosine kinase and carcinogenesis inhibitor activities. Genistein is practically insoluble in water and oil in the active form of aglicone, which presents a technical difficulty. To circumvent this problem, the encapsulation of genistein in phosphatidylcholine liposomes seems an efficient alternative for the improvement of solubility. In this work, genistein was encapsulated in phosphatidylcholine liposomes and the drugphospholipid interactions were characterized. It was demonstrated that the interaction of genistein with this lipid membrane model lead to an increased membrane rigidity caused by a tighter packing of the phospholipid bilayer. Encapsulation efficiency for genistein in liposomes reached 99%, with a maximum loading efficiency at the molar ratio of 1:3 (genistein:phosphatidylcholine), resulting in an increase of 1000 times in the water solubility of genistein. Genistein was able to protect membrane phospholipids against CuSO4 induced peroxidation. The liposomal preparation remained stable for at least 40 days, showing its potential as a nanostructured delivery system for this isoflavone for therapeutic and cosmetic applications.
Síntese e caracterização de peneira molecular mesoporosa mcm-41 com níquel impregnadas e in situ
(Universidade Federal de Goiás, 2008-05-14) KLEIN, Karina Vitti; NUNES, Liliane Magalhães; http://lattes.cnpq.br/6591210839894513
The new family mesoporosas molecular sieves, known as M41S, have been very studied since its discovery in 1992, with bigger prominence for MCM-41, that had its mesoporosa structure that allows ample applications in catalytic processes. In this work were studied two reactions conditions of preparation of the MCM-41 and three forms of nickel incorporation. In the synthesis of the MCM-41 the hidrotérmico treatment and in conditions was used surrounding, while in the incorporation, was used to impregnation of ions nickel and nanopartículas of nickel oxide, as well as the direct synthesis where the nickel was introduced in the structure of the MCM-41, during the synthesis. The gotten materials had been characterized by elementary nickel analysis, X-ray diffraction, nitrogen adsorption/desorption, FT-IR spectra, thermogravimetric analysis, thermoprogrammed reduction. The characterizations had indicated that it had the formation of the mesoporosa structure with periodic pore system, typical of the MCM-41, in both methods of synthesis, being able to be evidenced the biggest viability of the synthesis of the MCM-41 in the surrounding conditions. It can also be verified that it had nickel incorporation in all samples, independent of as this element was inserted. The introduced samples that had had nickel during the synthesis had presented greater excessively average diameter of pores in relation. After the characterization, the samples with nickel had been tested as in the reaction of conversion of carbon monoxide the high temperatures catalytic, known as HTS reaction, presenting activity.
Síntese e caracterização de catalisadores de óxido de ferro suportado em titanatos lamelares
(Universidade Federal de Goiás, 2008-05-19) BRASIL, Valéria Bacelar; NUNES, Liliane Magalhães; http://lattes.cnpq.br/6591210839894513
Sodium trititanate and silica - trititanate supported iron oxide catalysts were prepared by coprecipitation of iron ions and by the deposition of iron oxide nanoparticles previously prepared. The catalysts and the supports were characterized regarding their composition, structure, thermal behavior and textural properties. The amount of iron in catalysts ranged from 0.98% to 5.9%, and the lowest percentages were observed for catalysts prepared by deposition of nanoparticles. The catalysts and supports are macroporous with limited mesoporosity. The catalysts and supports were evaluated in the reaction of dehydrogenation of ethylbenzene for the production of styrene. During tests, the structure of the solids did not chang. Both the supports and the catalysts were active in the dehydrogenation of ethylbenzene in the absence of steam, allowing the economy of energy. The results of verification of the ionic exchange process/ adsorption of Cu+2, showed that the solids containing iron oxide in the composition presented results higher than the solids without iron oxide. The exception was observed for the solids that have acid surface.
NANOPARTÍCULAS MAGNÉTICAS FUNCIONALIZADAS COM BICAMADAS DE LAURATO/LAURATO E LAURATO/PLURONIC: ESTUDO DA ASSOCIAÇÃO COM ANFOTERICINA
(Universidade Federal de Goiás, 2008-05-27) SILVA, Joel Rocha da; LIMA, Emilia Celma de Oliveira; http://lattes.cnpq.br/0176904550618260
Magnetite nanoparticles were prepared by the coprecipitation of ions Fe2+ and Fe3+ using ammonia solution as precipitating agent. Maghemite nanoparticles were prepared by forced oxidation of magnetite nanoparticles in acidic medium using nitrate ions as oxidizing agent. The magnetic nanoparticles were used to the preparation of aqueous magnetic fluids samples by the functionalization of the nanoparticles with bilayers of laurate/laurate and laurate/Pluronic. Aliquots of the magnetic fluids were dried and the resultant powders were characterized by chemical analysis (the contents of ions Fe2+ and Fe3+), X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The contents of ions Fe2+ and Fe3+ in all the samples showed that the nanoparticles are not pure magnetite or maghemite phases. X-ray powder diffraction (XRD) indicated the existence of inverse cubic spinel phase, but didn't permit the distinction between magnetite and maghemite phases. Based on the results of chemical and XRD analyses, the nanoparticles could be better characterized as reduced maghemite, which mean maghemite phase containing ions Fe2+. The average sizes of the oxide nanoparticles estimated by XRD were around of 10 nm. FTIR analyses showed that the nanoparticles were functionalized with bilayers of laurate/laurate and laurate/Pluronic. FTIR analyses also were indicative of the maghemite phase. The hydrodynamic size of the functionalized nanoparticles measured by PCS were in the range of 70-90 nm for the samples based on laurate and in the range of 100-200 nm for the samples containing Pluronic. The measurements of zeta potential showed that the magnetic fluids based on laurate bilayers presented better colloidal stability than that one based on bilayers of laurate/Pluronic. On the other hand, the studies of colloidal stability in cell culture medium by hydrodynamic size measurements showed the lost of colloidal stability of all the samples, in all the concentrations of medium investigated. The fluids with laurate/laurate bilayers showed higher ratio of aggregation in the culture medium than the fluids with laurate/Pluronic. The association of amphotericin B with nanoparticles was carried out only using the samples with laurate bilayers. The results showed that the ratio of association depends on the concentration of amphotericin added to the magnetic fluid. It was observed 100% of amphotericin association in the range of nanoparticles/amphotericin concentrations used, which in turn are adequated for posterior in vivo studies
PREPARAÇÃO DE COMPÓSITOS DE POLIANILINA EM MATRIZES DE COPOLÍMEROS ESTIRENO-DIVINILBENZENO E ESTUDOS DE ADSORÇÃO POR TROCA IÔNICA DE ÂNIONS COMPLEXOS DE [FeCl4]- E [CuCl4]2-
(Universidade Federal de Goiás, 2008-06-30) SILVA, Robson Benedito; RABELO, Denilson; http://lattes.cnpq.br/4961539278604455; ALCÂNTARA, Edésio Fernandes da Costa; http://lattes.cnpq.br/1390296669687868
In this work, composites of dispersed polyaniline in beads of styrenedivinybenzene copolymer (Pani/Sty-DVB copopolymer) with different porosities were prepared through in situ polymerization. Materials with high surface areas and high porosities were obtained what explain their properties to adsorve transition metals. SD29 and SD84 copolymers were prepared through suspension polymerization in the presence of inert diluents as toluene/heptane with different DVB ratios to obtain macroporous beads. SD29/Pani and SD84/Pani composites were obtained by swelling the copolymers with aniline/ethanol mixtures (20/80%) before polymerization. Oxidative polymerization of aniline was carried out with ammonium persulfate in the presence of nitric acid at pH extremely acid and temperature range from 0 to 3 oC for 5 hours. All materials were characterized by infrared spectroscopy, porosity measurements, optical microscopy and adsorption capacity. The composite surface areas and pore volumes diminished in relation to original xv copolymers, while apparent density increased due polyaniline incorporation. Pore size distributions did not suffer large variations and all were typical of macroporous structures. Due the high DVB content, SD84/Pani composite and SD84 copolymer presented higher porosity and specific surface area when compared to systems with low reticulation degree. From acid solutions, [FeCl4]- and [CuCl4]2-, complex anions were adsorbed on SD29/Pani and SD84/Pani composites through ion exchange batch process. The amounts of complex anions adsorbed were determined by atomic absorption spectrophotometry. Complex anions adsorption increased with chloridric acid and metal concentration for both composites. Maximum adsorption capacity (mg of anion/g of composite) of [FeCl4]- were higher than [CuCl4]2- for both composites. Kinetic data showed a time of 12h for adsorption equilibrium of [FeCl4]- anions, while for [CuCl4]2- anions the equilibrium was not reached in 24 h for both composites. Infrared spectra showed vibrational bands of characteristic functional groups in the materials and band shifts were observed after [FeCl4]- and [CuCl4]2- complex anions adsorptions on the composites. Morphology evaluation showed that aniline polymerized homogeneously in the presence of nitric acid for all porous structures of the copolymers. Therefore, it can be concluded that complex anions adsorption depend as so the amount of adsorption sites of polyaniline as the porous structures of the composites.
CLASSIFICAÇÃO DE CERVEJAS POR ANÁLISE DE IMAGENS E PCA
(Universidade Federal de Goiás, 2008-06-30) SILVA, Thiago César de Oliveira; OLIVEIRA, Anselmo Elcana de; http://lattes.cnpq.br/0369339073291948
In this work a simple and new approach for lager beer pattern recognition based on image analysis was accomplished using Principal Component Analysis (PCA). Digital color images obtained from a scanner were decomposed into a binary form with the help of Scilab and SIP softwares. The PCA data matrix consisted of RGB color histograms for each sample. 350 mL beer cans were chosen at random on the shelf of local supermarkets in an overall of ninety cans from ten different brands. 200 mL samples were immersed in an ultrasound bath for a period of time ranging from twenty to thirty minutes before the digital image processing. The resulting methodology can be a simple alternative to the analytical quality control of lager beers.
ESTUDO DE FASES E CRESCIMENTO DE MONOCRISTAIS NO SISTEMA Bi2O3 - TiO2 - ZrO2
(Universidade Federal de Goiás, 2008-08-18) FERREIRA, Katiúscia Daiane; CARVALHO, Jesiel Freitas; http://lattes.cnpq.br/5841291496427516
I n this work a systematic study on the phase formation and stability in the system Bi2O3-ZrO2 was realized, the solubility of the Zr4+ ion in Bi12TiO20 (BTO) was investigated and Zr-doped BTO crystals (BTO:Zr) were grown and optically characterized. It was verified that a tetragonal phase was formed in the following wide composition interval: (6-x)Bi2O3:(1+x)ZrO2, with x = 0.5, 0.3, 0.2, 0.1, 0, -0.1, -0.2, -0.3, -0.5, -0.65 e -0.7. The phases were synthesized by solid state reaction and the powders were characterized by Xray diffraction and diferential thermal analysis. The formed tetragonal phase, however, was metastable for all investigated compositions and its preparation was dependent on the sample thermal history. The stable phase at room temperature was a monoclinic one. A low solubility of Zr4+ in BTO was verified, but BTO:Zr single crystals were grown by Top Seeded Solution Growth (TSSG) technique. Good quality crystalline samples were prepared and characterized by chemical compositon and by optical activity, photoconductivity and electro-optical measurements. The results shown that Zr-doping produced a decreasing in the crystal photosensitivity, and almost no changes in the optical activity and electro-optical coefficient were generated.
Avaliação e desenvolvimento de métodos de caracterização e controle de qualidade de biodieseis metílicos e etílicos por cromatografia gasosa capilar a altas temperaturas
(Universidade Federal de Goiás, 2008-09-01) REZENDE, Daniela Rodrigues de; ANTONIOSI FILHO, Nelson Roberto; http://lattes.cnpq.br/5982964870999454
In this work, a chromatographic method for simultaneous determination of free and total glycerol, mono-, di- and triacylglycerides contents in biodiesel it was evaluated. It s an alternative method for the reference ASTM D-6584 and EN 14105 standard methods with the advantages of being more practical, economical and faster. Moreover the method is applicable to methylic and ethylic biodiesel and biodiesel with long chain triacylglycerides. For this, High Temperature Capillary Gas Chromatography (HT-CGC) on short (15 m) and non-polar column (DB-5HT) and flame ionization detection were used. The accuracy of EN 14103 standard method in the determination of ester content in biodiesel also it was evaluated. Furthermore, a rapid chromatographic method for accompanying the conversion of fats and oils in biodiesel in function of alterations in the reactive conditions of the production system it is presented. For this, the same column and detector were used. The monitoring can be done in just 13 minutes of analysis and it was realized through of the relative proportion between methyl or ethyl esters and triacylglycerides total areas. In addition, the influence of silylation in the analysis of acylglycerides by gas chromatography was also investigated. Mono and diacylglycerides reference standards, silylated and non-silylated, were analyzed by HT-CGC. In non-silylated standards intramolecular reactions occurring inside the chromatographic column it was observed. It was verified that the intensity of these reactions depends on the type and unsaturation degree of the acylglycerides, of the carbon chain length, injection mode, injector temperature and column conditions. Therefore, silylation protects the hydroxyl groups for this kind of reaction and it is a necessary step in gas chromatographic analysis of mono- and diacylglycerides.
Síntese e caracterização de nanopartículas de maguemita recobertas com sílica funcionalizada com grupos amina
(Universidade Federal de Goiás, 2008-11-25) ALMEIDA, Michelly Patrícia Santana de; SARTORATTO, Patrícia Pommé Confessori; http://lattes.cnpq.br/9777959525393785
Magnetic nanoparticles coated with several kinds of materials have been the focus of intense research due to their potential applications in biomedicine. This type of material contains a magnetic core that is involved by a shell of different composition. The coating of magnetic nanoparticles with amino-functionalized silica is particularly important because of its reactivity which allows the coupling with biological molecules such as fragments of DNA, antibodies, proteins, among others. In this work, maghemite nanoparticles were coated with silica and with amino-functionalized silica, the incorporation of them being achieved by using tetraethoxysilane (TEOS) and aminopropyltrimethoxysilane (APTS) as the precursors of the sol-gel system. Firstly, the magnetic fluids of maghemita were prepared and afterwards they were employed in the silica-coating procedures which were based on the Stöber method. Some experimental parameters were varied, such as the number of maghemita nanoparticles, pH of the reaction medium, time of reaction and amount of TEOS, with the aim of modulating the characteristics of the solids and obtaining stable aqueous suspensions of the materials. All products were analyzed by the following techniques: X- ray diffraction, diffuse reflectance infrared spectroscopy, dynamic light scattering, electrophoretic mobility (zeta potential) and transmission electron microscopy.
SÍNTESE DE POLI (ÁCIDO LÁTICO-CO-ÁCIDO GLICÓLICO) ATRAVÉS DE POLICONDENSAÇÃO CATALISADA POR RESINA DE TROCA IÔNICA CONTENDO ÓXIDO DE ESTANHO COMO CO-CATALISADOR.
(Universidade Federal de Goiás, 2008-11-27) OLIVEIRA, Leonardo François de; RABELO, Denilson; http://lattes.cnpq.br/4961539278604455
In this study PLGA copolymers were synthesized with molecular weight above 10 kDa through direct polycondensation of L-lactic acid and glycolic acid monomers. Catalysts based on sulfonated styrenedivinylbenzene copolymer (SC) containing or not Sn2+ íons adsorbed as SnCl2.H2O colloidal particles from neutral solution or [SnCl3]- complex anions from acid solution were prepared. All catalysts were evaluated by specific surface area and pore volume measurements, infrared spectroscopy, X-ray diffraction, atomic absorption spectrophotometry and ion exchange capacity. The obtained PLGA copolymers were characterized by infrared spectroscopy, X-ray diffraction and inherent viscosity measurements. Independent of pH solution of the adsorptions, it was observed that Sn2+ ions were oxidized to Sn4+ forming SnO2. This oxidation probably occurred during catalysts drying process in the presence of oxygen. The PLGA copolymers with highest inherent viscosities, i.e., highest molecular weights were obtained with SC catalyst containing SnO2 prepared by adsorption of SnCl2.H2O colloidal particles in neutral solution. It was estimated that the highest PLGA molecular weights were equal or larger than 35 kDa. The produced PLGA presented white or lightly yellow color and Sn contamination less than 1 ppm which is below the limit allowed by the Brazilian legislation
Síntese e Caracterização de nanopartículas de maghemita revestidas com ácido oléico para obtenção de fluidos magnéticos a base de óleos isolantes
(Universidade Federal de Goiás, 2009-03-18) VIALI, Wesley Renato; SARTORATTO, Patrícia Pommé Confessori; http://lattes.cnpq.br/9777959525393785
In this work maghemite nanoparticles were synthesized by co-precipitating Fe2+ and Fe3+ in alkaline medium. The freshly prepared magnetite was oxidized by two different routes: by bubbling O2 through an acid suspension of magnetite nanoparticles or by hydrothermal treatment of magnetite with ferric nitrate/nitric acid solution. After oxidation, the nanoparticles were covered with oleic acid and the grafting coefficient was evaluated according to the oxidation method and pH employed in the adsorption experiments. The covered particles were dispersed in mineral and vegetable insulating oils, resulting in magnetic fluids whose colloidal stability was investigated in regard to the following parameters: dilution, heating, water content, chemical composition of insulating oils and addition of oleic acid. The nanoparticles were characterized by X-ray diffratometry, thermogravimetric and differential thermal analyses and infrared spectroscopy. The Fe3+/Fe2+ molar ratio in the solids was determined by UV-Vis spectrometry. The magnetic fluids were characterized regarding the volume fraction of nanoparticles, the water content, and their colloidal stability was monitored by dynamic light scattering measurements and visual observations. The results obtained from the analyses indicated that the oxidized magnetite nanoparticles (5 to 10 nm) have inverse spinel structure and Fe3+/Fe2+ molar ratio varied from 20 to 70, depending on the oxidation method and employed conditions. The grafting coefficient varied from 2,1 to 4,8, reflecting the oleic acid adsorption conditions, and the further treatments. It was also observed that by controlling the experimental conditions, a grafting coefficient very close to a Langmuir s monolayer can be achieved, together with a decrease in the amount of physisorbed species which contribute negatively to the colloidal stability. The study of colloidal stability showed that dilution, heating and XVII water content have a great influence in the sedimentation of diluted magnetic fluids, when they are diluted with minerals insulating oils. It was verified that the magnetic fluids diluted with vegetable insulating oil showed very high colloidal stability in the accelerated thermal aging experiment
Influência do biótipo de cor de fruto e da sazonalidade no óleo essencial das folhas Eugenia uniflora
(Universidade Federal de Goiás, 2009-03-27) COSTA, Deomar Plácido da; FERRI, Pedro Henrique; http://lattes.cnpq.br/2129799749473005
The multivariate chemical analysis of the essential oils from leaves of Eugenia uniflora with different fruit colour indicated the presence of three clusters of oils regarding sample biotypes. The first included yellowish-orange, purple, and dark red fruits with high percentages of germacrene B (11-31%), germacrone (9.8-54%) and atractylone (0-20%). In cluster II, with red bright fruit samples, the major constituents were curzerene (42-43%), germacrene D (8.7- 9.0%) and germacrene A (5.9-8.9%), while cluster III included red-orange fruit samples containing a high content of selina-1,3,7(11)-trien-8-one (40-55%) and selina-1,3,7(11)-trien-8-one epoxide (13-24%). All essential oils have predominantly sesquiterpenes, although sesquiterpene hydrocarbons and oxygenated sesquiterpenes contents were majorities in the clusters I/II and III, respectively. In addition, seasonal influence on the chemical composition of essential oils of from leaves of red-orange fruit colour biotype has indicated the influence of seasons, which included samples collected during dry months (April-September) characterized by the highest percentages of spathulenol (10%) and caryophyllene oxide (4.1%), and samples collected during wet months (October-March), whose major constituent was selina-1,3,7(11)-trien-8- one epoxide (29%). The canonical correlation indicated that spathulenol and caryophyllene oxide revealed a strong relationship with the phenolics and nutrient balance (S, Ca, Fe) in leaves, whereas selina-1,3,7(11)-trien-8-one epoxide was related to (K, Cu, Mn), and precipitation during the months of the wet season. Oxygenated sesquiterpenes were predominant in all the sampling months and the oil chemovariation observed might be environmentally determined by a clear seasonal influence.
Estudo da adsorção de íons ortofosfato em hidróxido de alumínio
(Universidade Federal de Goiás, 2009-05-26) DAMASCENO, Fernando Cruvinel; LIMA, Emilia Celma de Oliveira; http://lattes.cnpq.br/0176904550618260
Aluminum hydroxides are efficient phosphate adsorbents. In this work it was investigated the adsorptions of phosphate in three different forms of aluminum hydroxide (amorphous, bayerite and pseudo-boehmite). The adsorption isotherms present the amount of phosphate adsorbed as a functions of the equilibrium concentration of orthophosphate ions aqueous solutions, in pH = 5. The products of adsorption were characterized by infrared spectroscopy, 27Al e 31P NMR spectroscopy, XRD analysis, and by zeta potential measurements of the aqueous dispersions. The adsorption isotherms of phosphate on aluminum hydroxide showed that when the hydroxides are treated with diluted phosphate solutions (< 2,0 mmolL-1) the three hydroxides adsorb similar amount of phosphate. When the hydroxides are treated with concentrated phosphate solutions (> 2,0 mmolL-1) bayerite and amorphous aluminum hydroxide incorporate much more phosphate than pseudo-boehmite. The IR and the NMR 27Al and 31P analysis of the adsorption products showed that when the adsorption is carried out in low concentrate phosphate solutions, the adsorbed species are surface aluminum phosphate complexes, while in samples treated with concentrated phosphate solution the products of adsorption are solid phases of aluminum phosphate. These results suggest that the incorporation of phosphate by the three aluminum hydroxides studied occur in two steps. In the first step the phosphate are adsorbed yielding surface complexes; in the second step the incorporation of phosphate occur via the process of aluminum dissolution and precipitation of an aluminum phosphate phase. The XRD analysis showed that the precipitate formed during the dissolution-precipitation process is amorphous and become crystalline after heated at 750 °C for 30 min. The slope of the zeta potential measurements of the aqueous suspensions of the adsorption products suggests that the concentration of the phosphate solution at which the transition of phosphate incorporation by adsorption changes to phosphate incorporation by dissolution-precipitation is similar for the three hydroxides (2 mmolL-1). The results showed that the incorporation of phosphate by precipitation-dissolution occur on the three hydroxides but with lower extension on pseudo-bohemite. This behavior might by related to the lower dissolution of pseudo-bohemite because it is more condensed than amorphous aluminum hydroxide and bayerite
Contribuição ao estudo de espécies da familia Rubiacvea: Fitoquímica da espécie Amuaioua guianensis Aulb
(Universidade Federal de Goiás, 2009-06-05) OLIVEIRA, Pollyanna Laurindo de; OLIVEIRA, Cecilia Maria Alves de; http://lattes.cnpq.br/3152041311943092
Amaioua guianensis Aulb is a shurb best known as marmelada-brava or marmelinho-vermelho belonging to Rubiaceae family. Amaioua genus comprise 10 species which are distributed through Floresta Amazônica, Cerrado, Pantanal and Mata Atlântica. No phytochemical work has been reported on the leaves and bark of A. guianensis. As part of our ongoing search for new compounds from higher plants we undertaken and investigation of the ethanolic extract of A. guianensis as well as their antioxidant na molluscicidal activity. In this study we describe the isolation and structural elucidacion of a new conpound, a cyclopeptide (2), and twelve known compounds: a coumarin (1), two pentacyclic triterpene (3 and 4), mannitol (5), ethylglucose (6), three chorogenic acids (7, 8 and 9), two proanthocyanidins (10 and 11) and two steroids (12 and 13). The crude ethanolic extract, its purified fractions soluble in n-hexane, ethylacetate and methanolic, besides compounds 10 and 11 promptly reacted with DPPH leading to a loss of 50% in the absorbance activity in the concentrations of 78, 25, 246 and 4 μg/mL, respectively. The results of the molluscicidal assays with the crude ethanolic extract and its fractions indicated that ethylacetate fractions is the most active fraction with LC100 100 ppm and LC50 42,5 ppm
Estudo Fitoquímico das Folhas da Espécie Psychotria prunifolia (Kunth) Steyerm (Rubiaceae)
(Universidade Federal de Goiás, 2009-07-31) FARIA, Emiret Otoni de; KATO, Lucilia; http://lattes.cnpq.br/1362891438631386
Psychotria prunifolia is a Rubiaceae family specimen found in the Goiás cerrado , which is a huge ecosystem in the Brazilian Mid-West Mainland. The NCI (National Cancer Institute) highly referred to Psychotria as a hot genera with a cytotoxic potential from its extracts and fractions. Several related chemical studies have mostly indicated findings of indole alkaloid, which are keys to various biological activities. Current ongoing studies are focusing on phytochemical investigation of P. prunifolia, and its cytotoxic, antibacterial, antioxidant, and antifungal findings from its leaves extracts and fractions. It was feasible to isolate four new indole-monoterpene alkaloids and estrictosamida upon fractioning the leaves gross extracts. Estrictosamida has been found in and isolated from other specimens from the same genera. Recently-found alkaloids have been named prunifolina, prunifoliona, EPP26.2 e EPP28.1. Indole-monoterpene alkaloid is of greater chemotaxonomic importance for the Rubiaceae family, and it may assist with better classifying heteropsychotria sub-genera specimens. In vitro analysis of four cultures of cellular kinds, (S-180- Mice Sarcoma, A549- Human-Lung Carcinoma, K562 Chronic Human Myeloid Leukemia e HFF- 1-Regular Human Cells fibroblasts), has demonstrated successful cytotoxic activity of the P. prunifolia specimen. As a result of the antibacterial analysis, the leaves extracts were deemed to be less active. Extracts of leaves have shown little efficacy with its antioxidant potential, and in vitro antifungal analysis has indicated mild or little response.
Produção e Caracterização de Biocombustíveis por Craqueamento de Óleo Vegetais via Catálise com Bauxita
(Universidade Federal de Goiás, 2009-08-06) PRADO, Cinara Machado Rodrigues do; ANTONIOSI FILHO, Nelson Roberto; http://lattes.cnpq.br/5982964870999454
In this work, raw bauxite, thermally activated calcined bauxite, calcined bauxite underwent acid treatment were the catalysts tested by its potential in the thermal catalytic cracking reaction looking forward to the production of biofuels from commercial soybean oil as an alternative to fossil fuels. The materials were characterized by the techniques ICP-OES, infrared spectroscopy, thermal analysis, X-ray diffraction and textural analysis. The chromatographic analysis of the biofuels obtained by cracking of commercial soybean oil showed hydrocarbon compounds such as alkanes, alkenes and aromatics, as well as some oxygenated compounds such as carboxylic acids, ketones and alcohols. The products generated by the thermal catalytic cracking process with thermally activated calcined bauxite showed better results than the thermal cracking products because of the low quantity of acids present, which provided biofuels with a lower acidity index, and absence of acrolein. Therefore, the catalyst which was used demonstrated activity in the secondary cracking process, in which fatty acids decompose and give rise to hydrocarbons. The cracking tests with raw bauxite generated a lower biofuels yield and significant amount of solid product and residual oil making unfeasible the process. In order to evaluated the potential of used industrial waste sources for production of alternative fuels, the cracking of the waste vegetable oil studied together with the optimum of the reaction conditions obtained satisfactory result in the gaseous and liquid yield and percentage of crude biofuels generated. The biofuel presented similar composition observed in the biofuels obtained in thermal catalytic cracking of xv commercial soybean oil. This proved that the thermal catalytic cracking process is an alternative solution for the reutilization of waste vegetable oil and fats, both, when discarded inadequately can become environment pollutants

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