Editorial 30ª Reunião Anual: ano 30 da Sociedade Brasileira de Química Mangrich, Antonio Sálvio |
Artigo Synthesis and evaluation of the plant growth regulator property of indolic compounds derived from safrole Marchi, Irineu Rebelo, Ricardo Andrade Rosa, Flávia A. Fernandes da Maiochi, Riceli A. Abstract in English: The present work describes the use of piperonal, a derivative of the secondary metabolite safrole, for the synthesis of new 5,6-methylenedioxysubstituted indole carboxylic acids structurally related to the indol-3-yl-acetic acid (AIA, I). The route comprises six steps beginning with piperonal with an overall yield of 19%. Compound IX was tested towards its plant growth regulator properties in bioassays specific for auxine activity. The in vitro assays were performed in a germination chamber and were of two types: root growth in germinated seeds of Lactuca sativa, Cucumbis sativus and Raphanus sativus and peciole biotest using Phaseolus vulgaris. |
Mercury in soils and sediments from gold mining liabilities in Southern Amazonia Wasserman, Julio Cesar Campos, Reinaldo Calixto Hacon, Sandra de Souza Farias, Renato A. Caires, Sandro M. Abstract in English: The 1980-1990 Amazonian gold rush left an enormous liability that increasingly has been substituted by developing fish aquaculture. This work aimed at the identification of the mercury levels in the environment, associated with fish farms located in the North of Mato Grosso State, Southern Amazon. Sediment and soil samples were analyzed for total organic carbon and total mercury. Results indicate that the chemical characteristics of the sediment largely depend on the management procedures of the fish pond (liming, fish food used and fish population). The soils presented relatively low concentrations when compared with other data from the literature. |
Artigo Development and validation of the methodology for evaluation of itraconazole in pharmaceutical products by HPLC Cazedey, Edith Cristina Laignier Azevedo, Roberta de Cássia Pimentel Silva, Érika de Fátima Araújo, Magali Benjamim de Abstract in English: Itraconazole is a synthetic antifungal drug administered orally with a broad spectrum of activity against mycotic infections. The present work consists of the development and validation of analytical methodology for evaluation of itraconazole in pharmaceutical products by high performance liquid chromatography. The separation was made using the reversed-phase column LC-18, acetonitrile/diethylamine 0.05% v/v, 60:40 v/v, pH 8.0 as mobile phase, methanol as solvent and detection and quantification at 254 nm. The results here obtained show that the analytical methodology is accurate, reproducible, robust and linear over the concentration range 8.0-12.0 µg/mL of itraconazole. The method was applied to pharmaceutical capsules containg itraconazole pellets and showed to be efficient, yielding good results. |
Artigo Preperetion and physico-chemical characterization of inclusion complexes between local anesthetics and hydroxypropyl-<FONT FACE=Symbol>b</font>-cyclodextrin Moraes, Carolina Morales Abrami, Priscila Gonçalves, Marcos Moisés Andréo Filho, Newton Fernandes, Sérgio Antonio de Paula, Eneida Fraceto, Leonardo Fernandes Abstract in English: S(-) Bupivacaine (S(-)BVC) and Lidocaine (LDC) are widely used local anesthetics (LA). Hydroxypropyl beta-cyclodextrin (HP-beta-CD) is used as a drug-carrier system. The aim of this work was to characterize inclusion complexes between LA and HP-beta-CD. The affinity constants determined at different pHs show favourable complexation. The release kinetics experiments showed that S(-)BVC and LDC changed the released profiles in the presence of HP-beta-CD. Nuclear magnetic resonance experiments gave information about the interaction between LA and the cyclodextrin cavity. This study focused on the physicochemical characterization of drug-delivery formulations that come out as potentially new therapeutic options for pain treatment. |
Artigo Archaeometric analysis of Tupiguarani pottery from the central region of the Rio Grande do Sul State, Brazil, by energy dispersive X-ray fluorescence (EDXRF) Bona, Irene Akemy Tomiyoshi Sarkis, Jorge Eduardo S. Salvador, Vera Lucia Ribeiro Soares, André Luis Ramos Klamt, Sergio Célio Abstract in English: Energy dispersive X-ray fluorescence methodology (EDXRF) was used to determine Al, Ba, Ca, Cr, Fe, K, Mn, Pb, Rb, S, Si, Sr, Ti, V, Zn in pottery sherds from seven archaeological sites in the central region of Rio Grande do Sul State, Brazil. The potteries' chemical fingerprints from Ijuí River, Ibicuí Mirim River, Vacacaí Mirim River and Jacuí River were identified. Interactions between sites from the Jacuí River, Vacacaí Mirim River and Ibicui Mirim River could have occurred because some samples from these sites are overlapping in a principal component analysis (PCA) graphic. The pottery provenance could be the same. |
Artigo Relationship between charge transfer and intermolecular interactions in heterocyclic hydrogen-bonded complexes Oliveira, Boaz G. Araújo, Regiane C. M. U. de Abstract in English: Hydrogen-bonded complexes formed by the interaction of the heterocyclic molecules C2H4O and C2H5N with HF, HCN, HNC and C2H2 have been studied using density functional theory. The hydrogen bond strength has been analyzed through electron density charge transfer from the proton acceptor to the proton donor. The density charge transfer has been estimated using different methods such as Mulliken population analysis, CHELPG, GAPT and AIM. It has been shown that AIM-estimated charge transfer correlates very well with the hydrogen bond energy and the infrared bathochromic effect of the proton donor stretching frequencies. |
Artigo Statistical treatment of water quality parameters measured at the upper course of the Rio das Velhas basin Nonato, Eliana A. Viola, Zenilde G. G. Almeida, Katiane C. B. Schor, Heloiza H. R. Abstract in English: Water quality was monitored at the upper course of the Rio das Velhas, a major tributary of the São Francisco basin located in the state of Minas Gerais, over an extension of 108 km from its source up to the limits with the Sabara district. Monitoring was done at 37 different sites over a period of 2 years (2003-2004) for 39 parameters. Multivariate statistical techniques were applied to interpret the large water-quality data set and to establish an optimal long-term monitoring network. Cluster analysis separated the sampling sites into groups of similarity, and also indicated the stations investigated for correlation and recommended to be removed from the monitoring network. Principal component analysis identified four components, which are responsible for the data structure explaining 80% of the total variance of the data. The principal parameters are characterized as due to mining activities and domestic sewage. Significant data reduction was achieved. |
Urinary 2,5-hexanedione in workers exposed to n-hexane: influence of the sample treatment Nolasco, Daniela Magalhães Gusmão, Andréia Siqueira, Maria Elisa Pereira Bastos de Abstract in English: The aim of the present study was to determine 2,5-hexanedione (2,5-HD), a metabolite of n-hexane, by gas chromatography/flame ionization detection in 31 workers exposed to n-hexane after two types of sample pretreatment, i.e., with (total 2,5-HD) and without (free 2,5-HD) acid hydrolysis. The mean urinary 2,5-HD was 0.52 mg/L (free) and 2.88 mg/L (total), this difference being significant (Student t-test, p < 0.05). The differences in the results according to the sample treatment support the need to modify the current Brazilian legislation, which proposes the analysis of 2,5-HD without indicating whether it is the free or total metabolite. |
Artigo Adsorption of copper(II) on chitosan using a column in a closed hydrodynamic flow system Guinesi, Luciana Simionatto Esteves, Amanda Alves Cavalheiro, Éder Tadeu Gomes Abstract in English: The adsorption of Cu(II) ions from aqueous solution by chitosan using a column in a closed hydrodynamic flow system is described. The adsorption capacities as a function of contact time of copper(II) ions and chitosan were determined by varying the ionic strength, temperature and the flow of the metal solution. The Langmuir model reproduced the adsorption isothermal data better than the Freundlich model. The experimental kinetic data correlate properly with the second-order kinetic reaction for the whole set of experimental adsorption conditions. The rate constants exercise great influence on the time taken for equilibrium to be established by complexation or electrostatic interaction between the amino groups of chitosan and the metal. |
Artigo Evaluation of analytical variables of the Folin-Ciocalteu method for the quantitation of the total tannins content using a Psidium guajava L. leaves aqueous extract as a model Verza, Simone Gasparin Kreinecker, Maria T. Reis, Valquíria Henriques, Amélia T. Ortega, George González Abstract in English: The main analytical variables of a modified Folin-Ciocalteu method were studied by UV-Vis and gradient HPLC-PDA methods, using purified (PC) and technical grade (TGC) casein. Rutin and an aqueous extract of Psidium guajava L. leaves were used as models. The best results were ascribed to TGC. Certainly PC bonds the polyphenols of the P. guajava extract better than TGC, but TGC afforded better precision. A lack of specificity occurred when rutin was analyzed together with the P guajava extract. Additional analyses performed with the flavonoid fraction of P. guajava extract by HPLC-PDA had confirmed that casein was able to bind catechin, gallic acid and P. guajava flavonoids in a non-specific way. |
Artigo Determination of strontium isotopic composition in natural waters: examples of application in subsurface waters of the coastal zone of Bragantina region, Pará Bordalo, Adriana Oliveira Moura, Candido Augusto Veloso Scheller, Thomas Abstract in English: Analytical procedures used for determining the concentrations and isotope composition of strontium in subsurface waters, by mass spectrometry, are described. Sampling was performed in coastal plateaus, salt marsh and mangrove environments in the coastal region of Pará. Coastal plateau waters have delta87Sr between 1.51 and 6.26‰ and Sr concentration bellow 58 ppb. Salt marsh waters show delta87Sr between 0.55 and 0.90‰ and Sr concentration between 93 and 114 ppm, while mangrove waters have delta87Sr‰ around zero and Sr concentration above 15 ppm. Differences in the 87Sr/86Sr ratio in these subsurface waters are detected, as well as seasonal variations in the coastal pleteau waters. |
Artigo Canaric acid (3,4-seco-lupane derivative) isolated from propolis of Ceará Albuquerque, Irineu L. de Alves, Leonardo A. Lemos, Telma L. G. Monte, Francisco J. Q. Braz-Filho, Raimundo Abstract in English: Phytochemical investigation of a propolis sample from Alto Santo - Ceará, Brazil, allowed identification of triterpenes (lupeol, lupenone, germanicone, canaric acid) and flavonoids (quercetin, kaempferol and acacetin), which were identified by spectroscopic data (IR, MS, and NMR, including 2D techniques). This is the first report of canaric acid in propolis. Propolis extract and flavonoids showed antioxidant activity using a DPPH radical scavenging assay. |
Artigo Influence of plasticizer addition and crosslinking process on morohology, water absoption and mechanical properties of sodium alginate films Lima, Aline Margarete Furuyama Andreani, Larissa Soldi, Valdir Borsali, Redouane Abstract in English: The effects of sorbitol and formaldehyde on the morphology, water absorption and mechanical properties of sodium alginate films were analyzed. The morphology of the films indicated the presence of small aggregates in the surface of uncrosslinked films, which disappeared with the crosslinking process. The water uptake and percentage of elongation increased with the addition of sorbitol in uncrosslinked films. At the same time, a decrease in tensile strength and Young's modulus occurred. The swelling ratio and water uptake of crosslinked alginate/sorbitol films decreased with an increase in sorbitol content suggesting an enhanced crosslinking density due to the presence of plasticizer. |
Artigo Acaricidal activity of the essential oils leaves and fruits of Xylopia sericea St. Hill. on the two spotted spide mite (Tetranychus urticae Koch) Pontes, Wendel José Teles Oliveira, José Cândido Selva de Câmara, Cláudio Augusto Gomes da Gondim Júnior, Manoel Guedes Correia Oliveira, José Vargas de Schwartz, Manfred Oswald Erwin Abstract in English: The essential oils of the leaves and fruits obtained by hydrodistillation of Xylopia sericea, collected in the restinga area of Pernambuco, were analyzed by GC (HP 5890 SERIES II) and GC/MS (HP 5890B SERIES II/ MSD 5971). A major part of the volatile components identified in the oils of fruits and leaves were monoterpenes and sesquiterpenes. Cubenol (57.43%) and alpha-epi-muurolol (26.09%) were the main compounds found in the leaves, whereas beta-pinene (45.59%) and alpha-pinene (17.18%) were the fruits major components. The acaricidal activity of the essential oils was evaluated for Tetranychus urticae. The oil of the leaves was more active than that of the fruits showing an LC50 value of 4.08 µL/L of air for a 72 h period. |
Artigo Phytochemical study of the decoct from the leaves of Maytenus Truncata Reissek and the evaluation of the antinociceptive, antiedematogenic and antiulcerogenic activities of the decoct extracts Fonseca, Ana Paula Nascentes de Deus Silva, Grácia Divina de Fátima Carvalho, Juliana de Jesus Salazar, Gloria Del Carmen Meléndez Duarte, Lucienir Pains Silva, Renata Pamplona Jorge, Rodrigo Martinez Tagliati, Carlos Alberto Zani, Carlos Leomar Alves, Tânia Maria de Almeida Peres, Valdir Vieira Filho, Sidney Augusto Abstract in English: The present paper describes the phytochemical investigation and biological activities of the chloroform, ethyl acetate and methanol extracts of leaf decocts of M. truncata Reiss (Celastraceae). Our studies afforded two flavonoid glycosides, quercetin-3-O-rhamnopyranosyl-O-glucopyranosyl- O-rhamnopyranosyl-O-galactopyranoside (1) and kampferol-3-O-rhamnopyranosyl-O-glucopyranosyl- O-rhamnopyranosyl-O-galactopyranoside (2) from the methanolic extract and dulcitol (3) from the ethyl acetate extract. Ethyl acetate and methanol extracts exhibited considerable antiulcerogenic and analgesic activities. The results of the phytochemical studies suggest that the healing activity of methanol extracts can be related to the presence of glycosyl flavonoids. |
Content of flavonoids and phenolic compounds in chilean honeys. Orac index Muñoz, Orlando Copaja, Silvia Speisky, Hernan Peña, Raúl C. Montenegro, Gloria Abstract in English: A comparison of the phenolic content of several Chilean honeys showed great variations in flavonoid concentration among the samples analysed. Higher amounts of phenolics are found in honey from dry climates. The antioxidant effect of extracts, using ORAC analysis, did not correlate with the flavonoid content or with the total phenolic concentration. |
Artigo LS-SVM: a new chemometric tool for multivariate regression. Comparison of LS-SVM and pls regression for determination of common adulterants in powdered milk by nir spectroscopy Ferrão, Marco F. Mello, Cesar Borin, Alessandra Maretto, Danilo A. Poppi, Ronei J. Abstract in English: Least-squares support vector machines (LS-SVM) were used as an alternative multivariate calibration method for the simultaneous quantification of some common adulterants found in powdered milk samples, using near-infrared spectroscopy. Excellent models were built using LS-SVM for determining R², RMSECV and RMSEP values. LS-SVMs show superior performance for quantifying starch, whey and sucrose in powdered milk samples in relation to PLSR. This study shows that it is possible to determine precisely the amount of one and two common adulterants simultaneously in powdered milk samples using LS-SVM and NIR spectra. |
Correlation of anti-inflammatory activity with phenolic content in the leaves of syzygium cumini (l.) skeels (myrtaceae) Lima, Lucilene Azevedo Siani, Antonio Carlos Brito, Fabíola Almeida Sampaio, André Luís Franco Henriques, Maria das Graças Müller Oliveira Riehl, Carlos Alberto da Silva Abstract in English: Phenolic contents of extracts of Syzygium cumini leaves, collected monthly over a one-year period, were quantitatively determined by the modified Folin-Ciocalteau method. Extracts and tannin-free fractions were assayed by their potential to inhibit mouse paw edema induced by C48/80. HPLC showed high molecular weight phenolic species and flavonoids in the active extracts and fractions. The highest total phenolic content corresponded to the most potent degree of inhibition and the flavonoids were supposed to be the main species responsible for the activity, given that the flavonoid-enriched ethyl-acetate fraction maintained its effect down to a dose of 0.01 mg/kg in a dose-response manner. |
Artigo Identification of the influence of sludge discharges from water treatment plants Reis, Edson Luís Tocaia dos Cotrim, Marycel Elena Barbosa Rodrigues, Cláudio Pires, Maria Aparecida Faustino Beltrame Filho, Osvaldo Rocha, Solange Martone Cutolo, Silvana Audrá Abstract in English: The growing concern of environmental surveillance of the quality of hydric resources guides the development of research on management of residues generated in water treatment plants (WTP). Approximately 8.000 WTPs in Brazil operate without a treatment program of the residues, disposing these effluents in the environment. This work evaluated WTP discharges into watercourses by collecting superficial waters, sediments and benthic samples at the town of Registro, São Paulo State, Brazil. Even though superficial waters and benthic samples showed no further contamination, sediment analysis pointed out that aluminum deposits detected near sludge discharges may represent a potential risk to the environment. |
Artigo Characterization of liquid products and char from the pyrolysis of eucalyptus sawdust Martins, Ayrton F. Diniz, Juraci Stahl, João A. Cardoso, André de L. Abstract in English: This study proposes the low temperature pyrolysis as an alternative conversion process for residual biomass and for obtaining gaseous, liquid and solid chemical feedstocks. Using a bench electrical pyrolysis oven, four product fractions from eucalyptus sawdust were obtained: a gaseous one, two liquid (aqueous and oily), and a solid residue (char). These products were characterized by different analytical methods. The liquid fractions showed themselves as potential sources for input chemicals. The residual char revealed appreciable adsorption capability. The process demonstrated good efficiency, generating at least two fractions of great industrial interest: bio oil and char. |
Artigo Development of a method employing chitosan to remove metallic ions from wastewater Janegitz, Bruno Campos Lourenção, Bruna Cláudia Lupetti, Karina Omuro Fatibello-Filho, Orlando Abstract in English: In this work a method was developed for removing metallic ions from wastewaters by co-precipitation of Cu2+, Pb2+, Cd2+, Cr3+ and Hg2+ with chitosan and sodium hydroxide solution. Solutions of these metallic ions in the range from 0.55 to 2160 mg L-1 were added to chitosan dissolved in 0.05 mol L-1 HCl. For the co-precipitation of metal-chitosan-hydroxide a 0.17 mol L-1 NaOH solution was added until pH 8.5-9.5. A parallel study was carried out applying a 0.17 mol L-1 NaOH solution to precipitate those metallic ions. Also, a chitosan solid phase column was used for removing those metallic ions from wastewaters. |
Heavy metals and toxicity of waters of the Aconcagua River in Chile Gaete, Hernán Aránguiz, Fernanda Cienfuegos, Gabriela Tejos, Marisol Abstract in English: The toxicity of surface waters in a zone with mining activity in the Aconcagua River was determined through growth inhibition bioassays of Pseudokirchneriella subcapitata, and correlated with heavy metal concentrations. Results show that the waters near the discharge of the mining effluent displayed toxicity during all periods of study; the molybdenum and copper concentration exceeded the norms of water quality. The correlations between the concentrations of metals and the growth rate of P. subcapitata varied in the different periods of the study; inverse and significant correlations with copper stand out in some periods. |
Artigo Study of the influence of K+, Mg2+, SO4(2-) and CO3(2-) ions in the biomimetic crystallization of amorphous calcium phosphate (ACP) and conversion into octacalcium phosphate (OCP) Aparecida, Anahí Herrera Fook, Marcus Vinícius Lia Santos, Márcio Luis dos Guastaldi, Antonio Carlos Abstract in English: The crystallization of hydroxyapatite (HA) in aqueous solution can be described by the mechanism ACP -> OCP -> HA. In this work, it was studied the influence of K+, Mg2+, SO4(2-) and CO3(2-) ions in the formation of ACP and in its conversion to OCP, using biomimetic coatings on metallic substrates of commercially pure titanium (Ti c.p.). The results showed that Mg2+ and CO3(2-) ions favored both the formation of ACP and its conversion to OCP. Differently, K+ and SO4(2-) ions did not influence the formation of ACP and, consequently, interfered in the conversion to OCP. |
Artigo Triplet excited state reactivity of 1,3-indandione in benzene solution Santos, Frances R. dos Silva, Mônica T. da Netto-Ferreira, José Carlos Lucas, Nanci C. de Abstract in English: Rate constants for the quenching of 1,3-indandione (1) triplet by olefins and by hydrogen and electron donors were obtained employing the laser flash photolysis technique in benzene solution. These rate constants ranged from 2.5x10(5) Lmol-1s-1 (for 2-propanol) to 5.9x10(9) Lmol-1s-1 (for DABCO). From the quenching rate constants by 1,3-cyclohexadiene, trans- and cis-stilbene a value between 49.3 and 52.4 kcal/mol was estimated for the energy of the triplet state of 1,3-indandione. The npi* character of this triplet state was evidenced by the quenching rate constants obtained when typical hydrogen donors were employed as quenchers. For 2-phenyl-1,3-indandione (2, R=phenyl) a fast Norrish type I reaction is operating which prevents the determination of kinetic and spectroscopic data of its triplet state. |
Chemical constituents from Bakeridesia pickelii Monteiro (Malvaceae) and the relaxant activity of kaempferol-3-O-beta-D-(6"-E-p -coumaroyl) glucopyranoside on guinea-pig ileum Costa, Danielly Albuquerque da Silva, Davi Antas e Cavalcanti, Aline Coutinho Medeiros, Marcos Antônio Alves de Lima, Julianeli Tolentino de Cavalcante, José Marcílio Sobral Silva, Bagnólia Araújo da Agra, Maria de Fátima Souza, Maria de Fátima Vanderlei de Abstract in English: The phytochemical investigation of Bakeridesia pickelii Monteiro led to the isolation of seven compounds: beta-sitosterol, a mixture of sitosteryl-3-O-beta-D-glucopyranoside and stigmasteryl-3-O-beta-D-glucopyranoside, vanillic acid, p-coumaric acid, quercetin 3-O-beta-D-glucopyranoside (isoquercitrin) and kaempferol-3-O-beta-D-(6"-E-p -coumaroyl) glucopyranoside (tiliroside), which was isolated as the major component. Their structures were elucidated on the basis of spectroscopic data such as IR, ¹H and 13C NMR, including two-dimensional techniques. Tiliroside relaxed the guinea-pig ileum pre-contracted with KCl 40 mM (EC50 = 9.5 ± 1.0 x 10-5 M), acetylcholine 10-6 M (EC50 = 2.3 ± 0.9 x 10-5 M) or histamine 10-6 M (EC50 = 4.1 ± 1.0 x 10-5 M) in a concentration-dependent manner. |
Electrical and magnetic properties of new compounds of the conductor anion [Ni(dmit)2]- and nitronyl nitroxide magnetic radicals Dias, Mauro Cesar Stumpf, Humberto Osório Sansiviero, Maria Terezinha Caruso Pernaut, Jean Michel Matencio, Tulio Knobel, Marcelo Cangussu, Danielle Abstract in English: Three compounds have been synthesized with formulae [3-MeRad][Ni(dmit)2] (1), [4-MeRad][Ni(dmit)2] (2) and [4-PrRad][Ni(dmit)2] (3) where [Ni(dmit)2]- is an anionic pi-radical (dmit = 1,3-dithiol-2-thione-4,5-dithiolate) and [3-MeRad]+ is 3-N-methylpyridinium alpha-nitronyl nitroxide, [4-MeRad]+ is 4-N-methylpyridinium alpha-nitronyl nitroxide and [4-PrRad]+ is 4-N-propylpyridinium alpha-nitronyl nitroxide. The temperature-dependent magnetic susceptibility of 1 revealed that an antiferromagnetic interaction operates between the 3-MeRad+ radical cations with exchange coupling constants of J1 = - 1.72 cm-1 and antiferromagnetism assigned to the spin ladder chains of the Ni(dmit)2 radical anions. Compound 1 exhibits semiconducting behavior and 3 presents capacitor behavior in the temperature range studied (4 - 300 K). |
Artigo Adsorption behavior of polymer-based drilling fluids on SiO2 Queiroz Neto, João C. Biscaia Jr, Evaristo Chalbaud Petri, Denise F. S. Abstract in English: Polysaccharide-based drilling fluids have been often applied in horizontal wells of petroleum reservoirs in Campos, Rio de Janeiro. The present study aimed to understand the mechanism of adsorption and desorption of the drill-in fluid, xanthan, modified starch and lubricant on SiO2 by means of ellipsometry. The effect of pH and brine on the mean thickness (D) of adsorbed layer was systematically investigated. The adsorption was mainly favored under alkaline conditions. A model has been proposed to explain this effect. The adsorption isotherms determined separately for xanthan and starch on SiO2 surfaces could be fitted with the Langmuir model, which yielded similar adsorption constant values. |
Identification of acetates in elasmopalpulus lignosellus pheromone glands using a newly created mass spectral database and kóvats retention indices Jham, Gulab N. Silva, Alexsandro A. da Lima, Eraldo R. Viana, Paulo A. Abstract in English: Based on a specially created mass spectral database utilizing 23 tetradecenyl and 22 hexadecenyl acetate standards along with Kóvats retention indices obtained on a very polar stationary phase [poly (biscyanopropyl siloxane)] (SP 2340), (Z)-9-hexadecenyl acetate, (Z)-11-hexadecenyl acetate and (E)-8-hexadecenyl acetate were identified in active pheromone extracts of Elasmopalpus lignosellus. This identification was more efficient than our previous study using gas chromatography/mass spectrometry with a dimethyl disulfide derivative where we could only identify the first two acetates. The acetate composition of the pheromone gland differed from region to region in Brazil and from that from the Tifton (GA, USA) population, suggesting polymorphism or a different sub-species. |
Determination of chemical elements in africanized Apis mellifera (Hymenoptera: Apidae) honey samples from the State of Piauí, Brazil Sodré, Geni da Silva Marchini, Luís Carlos Zucchi, Orgeda Luiza Araújo Domingues Nascimento Filho, Virgilio Franco Otsuk, Ivani Pozar Moreti, Augusta Carolina de Camargo Carmello Abstract in English: Honey is a food used since the most remote times, appreciated for its characteristic flavor, considerable nutritional value and medicinal properties; however, little information exists about the presence of chemical elements in it. The objectives of this work were to determine the chemical elements present in 38 honey samples, collected directly from beekeepers from the State of Piauí, Brazil and to verify whether they presented any contamination. The chemical elements were determined by means of Total Reflection X-ray Fluorescence. The means of three replicates were: K (109.671 ± 17.487), Ca (14.471 ± 3.8797), Ti (0.112 ± 0.07), Cr (0.196 ± 0.11), Mn (0.493 ± 0.103), Fe (1.722 ± 0.446), Co (0.038), Ni (0.728 ± 0.706), Cu (0.179 ± 0.0471), Zn (0.967 ± 0.653), Se (not detected), Br (not detected), Rb (0.371 ± 0.097), Sr (0.145 ± 0.45), Ba (11.681), Hg (not detected), and Pb (0.863) µg g-1. |
Artigo Synthesis and catalytic properties on oxidation reaction of goethite containing niobium Oliveira, Luiz C. A. Gonçalves, Maraísa Oliveira, Diana Q. L. Guarieiro, Aline L. N. Pereira, Márcio C. Abstract in English: Nb-substituted goethites have been prepared and characterized by Mössbauer spectroscopy, XRD, SEM and BET surface area measurements. Mössbauer and XRD analyses suggested that Nb replaces Fe3+ in the structure with duplet formation. The insertion of Nb into the goethite structure caused a significant increase in the BET surface area of the material. The prepared alpha-Fe1-xNb xOOH was investigated for the H2O2 decomposition to O2 and for the Fenton reaction to oxidize the dye methylene blue. It was observed that the introduction of Nb in to goethite produced a strong increase in the activity of oxidation of the dye contaminant by H2O2. |
Artigo Oligonucleotide adsorption on nanoemulsions obtained by spontaneous emulsification Martini, Érico Carvalho, Edison Teixeira, Helder Leão, Fabiana Oliveira, Mônica Cristina de Abstract in English: This paper describes the adsorption of an oligothymidylate (pdT16) on nanoemulsions obtained by spontaneous emulsification procedures. Formulations were composed by medium chain triglycerides, egg lecithin, glycerol, water (NE) and stearylamine (NE SA). After optimization of operating conditions, the mean droplet size was smaller than 255 nm. Adsorption isotherms showed a higher amount of pdT16 adsorbed on cationic NE SA (60 mg/g) compared to NE (20 mg/g). pdT16 adsorption was also evidenced by the inversion of the zeta-potential of NE SA (from +50 to -30 mV) and the morphology of oil droplets examined through transmission electron microscopy. The overall results showed the role of electrostatic interactions on the adsorption of pdT16 on the oil/water interface of nanoemulsions. |
Revisão Occurrence and biological activity of quassinoids in the last decade Almeida, Maria Mozarina Beserra Arriaga, Ângela Martha Campos Santos, Allana Kellen Lima dos Lemos, Telma L. G. Braz-Filho, Raimundo Vieira, Ivo J. Curcino Abstract in English: Quassinoids, the bitter principles of the Simaroubaceae family, are a group of structurally complex and highly oxygenated degraded triterpenes. They are divided into five groups according to their basic skeleton, C-18, C-19, C-20, C-22 and C-25. In recent years, attention has been focused on quassinoids because several of them have shown promising biological activities. This paper features a review of some characteristics of these compounds, updating known information with discoveries from the last decade and covering chemical structures, basic skeletons, occurrence in genus and species, besides detailed studies of biological activities such as antitumor, antimalarial, phytotoxic, antifeedant, insecticidal, anti-inflammatory and antiulcer. |
Revisão Thermal analysis applied to the study of energetic materials Andrade, Jony Iha, Koshun Rocco, Jose Atílio Fritz Fidel Bezerra, Eduardo Marcelo Suárez-Iha, Maria Encarnación Vázquez Pinheiro, Glaci Ferreira Martins Abstract in English: This paper shows different aspects related to the application of different thermal analysis techniques in the study of energetic materials. The criteria used to choose the best technique and an exact approach to adjust the experimental data with a proper model are here discussed. The paper shows how to use the different thermal analysis results to help develop new compounds, to study the stability of some energetic materials and their compatibility, and the conditions necessary for a secure storing environment. |
Revisão Recent preparations and synthetic applications of enaminones Ferraz, Helena M. C. Gonçalo, Erika R. S. Abstract in English: Enaminones are beta-enamino carbonylic compounds bearing the conjugated system N-C=C-C=O, which makes them versatile ambident synthetic building blocks, particularly in synthesis of heterocycles. This review covers the last three years of the literature concerning the preparation and synthetic applications of enaminones. |
Revisão Enzymatic membrane reactor and supercritical fluids: process association Moura, Juliana Maria Leite Nóbrega de Ribeiro, Ana Paula Badan Grimaldi, Renato Gonçalves, Lireny Aparecida Guaraldo Abstract in English: The aim of this work is to present the new applications of membrane technology in fat and oil processing, with emphasis on development and applications of the enzymatic membrane reactor and its association with extraction and purification technology by supercritical fluids (SCF). Combining the extraction by SCFs and the separation by membranes allows the integration of extractions reactions with selective separation by membranes through filtration of the supercritical mixture (SCF + extracted solutes). This association provides important energy savings regarding the SCF recompression costs. |
Revisão Indole alkaloids from species of the Aspidosperma (Apocynaceae) genus Pereira, Maria de M. Jácome, Rose Lisieux R. P. Alcântara, Antônio Flávio de C. Alves, Rosemeire B. Raslan, Délio S. Abstract in English: Species from genus Aspidosperma (Apocynaceae) are popularly employed to treat various diseases. This genus is characterized by the occurrence of indole alkaloids. Taking into account the various biological activities attributed to these alkaloids, the description of the chemical diversity in genus Aspidosperma is important. A review of simple carbolinic alkaloids isolated from species of various genera was published in 1979. In 1987, it was published another one dealing with the relationships between the chemical structures of the indole alkaloids and the evolution of Aspidosperma species. This work updates the information about the indole alkaloids isolated from Aspidosperma species. |
Revisão Flavonoidic biodiversiy and pharmacologic aspects in the species of the Ouratea and Luxemburgia genera (Ochnaceae) Suzart, Luciano R. Daniel, Juliana F. de S. Carvalho, Mário G. de Kaplan, Maria Auxiliadora Coelho Abstract in English: This work describes the flavonoids and biflavonoids found in species of Ouratea and Luxemburgia as chemical markers that serve to detect the difference between these taxa according to the linkage between the flavonoidal units. A rational nomenclature is proposed and the pharmacological potencial is discussed. |
Divulgação Photodynamic inactivation of microorganisms Perussi, Janice Rodrigues Abstract in English: Photodynamic Therapy uses photosensitive dyes and visible light that, combined in the presence of oxygen, produce cytotoxic species that cause tumor death. Microorganisms such as bacteria, fungi, yeasts and viruses (including HIV) can also be inactivated by visible light after treatment with an appropriate photosensitizer as an alternative low cost treatment for localized infections, viral lesions such as acnes, and fungical skin lesions for example. Besides, Photodynamic Inactivation can be used for sterilization of blood and its subproducts for clinical use, in the treatment of drinking water as well as in antimicrobial detoxification of foods. |
Nota técnica Recovery of cobalt and lithium fromspent Li-ion batteries Busnardo, Natália Giovanini Paulino, Jéssica Frontino Afonso, Julio Carlos Abstract in English: The "active mass" (cathode + anode + electrolyte) of spent Li-ion batteries was submitted to one of the following procedures: (a) it was calcined (500 ºC) and submitted to extraction with water to recover lithium salts. The residual solid was treated with sulfuric acid containing hydrogen peroxide. Cobalt was recovered as sulfate; (b) the "active mass" was treated with potassium hydrogen sulfate (500 ºC) and dissolved in water. Cobalt was precipitated together with copper after addition of sodium hydroxide. Lithium was partially recovered as lithium fluoride. Co-processing of other battery components (aluminum and copper foils) affected negatively the behavior of the recovery procedures. Previous segregation of battery components is essential for an efficient and economical processing of the "active mass". |
Nota técnica Validation of analytical methodology by hplc for quantification and stability evaluation of sodium pantoprazole Raffin, Renata Platcheck Colomé, Letícia Marques Guterres, Sílvia Stanisçuaski Pohlmann, Adriana Raffin Abstract in English: Pantoprazole is a proton pump inhibitor used in the treatment of digestive ulcers, gastro-esophageal reflux disease and in the eradication of Helicobacter pylori. In this work, an analytical method was developed and validated for the quantification of sodium pantoprazole by HPLC. The method was specific, linear, precise and exact. In order to verify the stability of pantoprazole during dissolution assays, pantoprazole solution in phosphate buffer pH 7.4 was kept at room temperature and protected from light for 22 days. Pantoprazole presented less than 5% of degradation in 6 hours and the half live of the degradation was 124 h. |
Nota técnica Determination of edta content in cleaning solutions after their use in industrial equipaments Rodella, Arnaldo Antonio Abstract in English: Cleaning solutions containing EDTA are widely employed to remove incrustation despite of the costs involved. The free content of EDTA in commercial solutions may be determined by mixing an aliquot to ammonium oxalate and using a standard calcium solution as titrant. The end-point is detected by the formation of insoluble calcium oxalate after all EDTA is complexed. A system for turbidimetric detection of the end-point was envisaged to substitute the visual detection, which impaired the analyses of dark samples. The proposed method was tested with real samples and good accuracy and precision was obtained. |
Nota técnica Content of ethyl carbamate and other secondary compounds in different spirits produced in three regions of Minas Gerais: south minas, zona da mata and jequitinhonha valley Barcelos, Luciene Viana Ferreira Cardoso, Maria das Graças Vilela, Fernando José Anjos, Jeancarlo Pereira dos Abstract in English: Minas Gerais is the highest producer of handmade spirits. Research has been carried out aiming to contribute to progress. Thus, the goal of this work is to evaluate the quality of spirits in three different regions of Minas Gerais state. We analyzed ethyl carbamate, alcoholic grade, volatile acidity, higher alcohols, aldehyde, esters, methanol, furfural and copper. The values obtained for ethyl carbamate varied from undetectable to 643.5 µg L-1, with only one region not following the legislation (150 µg L-1). Most of the compounds in the spirits were present within the limits estabilished by the legislation. |
A technique for high recoveries from vacuum distillations Langler, Richard F. Abstract in English: The design and use of a novel apparatus for a variant of vacuum distillation is described. Relative to a conventional device, the apparatus/technique described permits superior recovery of multigram quantities of moderately volatile liquids from vacuum distillations. |
Educação Spectrophotometric titrations of acid-base systems using flower extracts containig anthocyanins Cortes, Mônica Souza Ramos, Luiz Antônio Cavalheiro, Éder Tadeu Gomes Abstract in English: Considering the attraction of the students' attention by the changes in the colors of vegetable crude extracts caused by the variation of the pH of the medium, the use of these different colors in order to demonstrate principles of spectrophotometric acid-base titrations using the crude extracts as indicators is proposed. The experimental setup consisted of a simple spectrophotometer, a homemade flow cell and a pump to propel the fluids along the system. Students should be stimulated to choose the best wavelength to monitor the changes in color during the titration. Since the pH of the equivalence point depends on the system titrated, the wavelength must be properly chosen to follow these changes, demonstrating the importance of the correct choice of the indicator. When compared with the potentiometric results, errors as low as 2% could be found using Rhododendron simsii (azalea) or Tibouchina granulosa (Glory tree, quaresmeira) as sources of the crude extracts. |
Educação Alkaline battery: a useful device in the teaching of chemistry Matsubara, Elaine Y. Neri, Cláudio R. Rosolen, J. Maurício Abstract in English: This paper presents the alkaline battery (MnO2/Zn) as a useful device in the teaching of chemistry. The preparation of the battery, the materials used in the preparation of the MnO2 electrode, the mechanism of energy storage and the parameters often used in the understanding of general batteries are discussed in detail. In addition, a schedule and a questionnaire that can be applied in an experimental class have been developed, which allow the assembly of an alkaline battery, its discharge using a galvanostatic or a load-resistance procedure, and the elaboration of a report based on the main text. This experimental class has been offered in the chemistry course of FFCLRP. |
Educação General scheme for elucidating the structure of organig compounds using spectroscopic and spectrometric methods Ribeiro, Carlos Magno R. Souza, Nelson Ângelo de Abstract in English: This work describes a systematic method to be applied in undergraduate courses of organic chemistry, correlating infrared spectra, hydrogen and carbon-13 nuclear magnetic resonance, and mass spectra. To this end, a scheme and a table were developed to conduct the elucidation of the structure of organic compounds initially using infrared spectra. Interpretation of hydrogen and carbon-13 nuclear magnetic resonance spectra and of mass spectra is used to confirm the proposed structure. |
Assuntos gerais The route of the studies of cochineal in Portugal and Brazil in the nineteenth century: uncrossed paths Ferraz, Márcia Helena Mendes Abstract in English: For imparting an intense and long-lasting red to fabrics, cochineal remained in high demand during the eighteenth and nineteenth centuries. This period witnessed, accordingly, several initiatives aimed at producing the precious dye: publication of specialized texts, cultivation of the cactus and the insect from which the dye is extracted, and, also, attempts to obtain the secrets of production through espionage. The present paper analyses certain aspects of the measures adopted by the Portuguese government towards Brazil in this field. The work shows how people sought to take part in the network of cochineal production (yet they were unsuccessful most of the time). |
Assuntos gerais From doctrine to practice: Ezequiel Corrêa dos Santos and national pharmacy Santos, Nadja Paraense dos Abstract in English: This article presents a sample of the activities of apothecary Ezequiel Corrêa dos Santos. He was notable not only for his professional career, but also for his political militancy, making an important contribution to the development of pharmaceutical sciences in Brazil, in the XIXth century. |
Assuntos gerais Vladimir Prelog and the stereochemistry of organic molecules: a centenary of birt Rezende, Claudia M. Abstract in English: The Croatian chemist Vladimir Prelog shared in 1975 the Nobel Prize in chemistry with J. W. Cornforth for his research into the stereochemistry of organic molecules and reactions. His studies gave new horizons to the comprehension of steric effects on the reactivity of medium-sized rings, to conformational analysis and to the stereospecificity associated to asymmetric syntheses. Prelog made important contributions to enzyme chemistry and to the structure elucidation of alkaloids and of antibiotics from microorganisms, but probably his most famous work is the CIP system for assigning the stereochemistry of chiral centers. |