Repositório RCAAP

Fundação de Amparo a Pesquisa no Estado do Rio Grande do Sul

The present study reason about the perception of professionals who act in the three complexity levels of the Sistema Único da Assistência Social (SUAS), concerning the streetlife experience of teenagers and children.. Seeking to identify how these professionals perceive the movement between the exit from home and the permanency on the streets and the implications of this dynamic on the constitution of the subjectivity of teenagers and children. Also, seeking to know if in the perception of these professionals the public politics of social protection, especially the ones focused on homeless people, contemplate the phenomena of streetlife experience of teenagers and children. Aiming at reach such goals a qualitative study with exploratory character with psychologists and social workers professionals was performed. A semistructured interview was used as a tool, it occurred from three guiding principles: 1) homelessness and family relations; 2) homelessness and subjectivity and 3) homelessness and public politics of social protection for people in homelessness situation. The data were analyzed through thematic content analysis and the research results will be presented and discussed in two articles which compose this thesis. The first article discusses the delicate embrittlement of the family bonds and the streetlife experience of teenagers and children, a category which emerged from the first guiding principle. On this article the aspects which gained prominence in relation to the reasons that lead teenagers and children to leave their houses and seek the streets as a survival alternative, namely: intrafamily violence, drugs abuse and poverty, are approached. The second article discusses three categories which emerged from the second and third guiding principles, namely: liberty and friendship; protective relations through groups formation; and the place of public politics in between the exit from home and the street permanency. The importance of public politics of social protection to childhood and youth as being an important instrument to professionals who act in the Sistema de Garantia de Direitos, especially of the Sistema Único da Assistência Social on its three levels of complexity: CRAS, CREAS e Acolhimento Institucional was emphasized. Finally, for children and teenagers with street life experience, this territory presents itself as a great paradox, because even exposing them to several danger factors, the street fulfills an important function, since it allows them the construction of meaningful relations that can influence greatly on the process of subjectiveidentity constitution, it was considered according to the point of view of the professionals who compose the study.

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A rapid digestion procedure for further determination of inorganic elements in carbon black-containing elastomers has been developed using sample combustion in closed quartz vessels with oxygen pressure. Microwave radiation was used for the ignition step. Samples containing high levels of carbon black (up to 30%) were digested using the proposed procedure: nitrile-butadiene rubber (NBR) and ethylenepropylene-diene monomer (EPDM). A quartz device was used simultaneously as a sample holder and for the protection of vessel cap. Sample was pressed as pellet and placed together a small piece of low-ash content paper in the holder. Ammonium nitrate solution (50 ml of 50% m/v) was added to the paper as aid for ignition. The influence of the absorption solution (nitric acid or water) and the necessity of an additional reflux step were evaluated. Determination of Al, Fe, Mn, Sr and Zn was performed by inductively coupled plasma optical emission spectrometry. A reference method (ASTM D 4004-064) based on conventional dry ashing followed by flame atomic absorption spectrometry determination was used for results comparison (Mn and Zn). Results were also compared to those obtained by using wet acid digestion in closed systems. As no certified reference elastomers were available analyte spikes were made for NBR and EPDM digests. Concentrated and diluted (4 mol l-1) nitric acid, with 5 min for reflux step after the combustion process, gave better recoveries for all analytes (from 97 to 101%). For Al and Mn recoveries were bellow 90% for both open and closed vessels using HNO3 and H2SO4 mixture. For dry ashing quantitative recoveries were found only for Zn (for Al recovery was 14%). Residual carbon content was bellow 0.5% for the proposed procedure. With the proposed procedure further determination of Al, Mn, Sr and Zn is feasible with only the combustion step but for Fe a reflux with diluted HNO3 was necessary. Then, using the proposed procedure complete sample digestion is obtained is less time than other procedures and no need of concentrated acids was considered necessary.

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The use of pesticides to control pests, diseases and weeds in crops of agricultural interest aims at the increase of production. The degradation of applied compounds or their conversion into other products, does not necessarily mean the loss of biological activity, and many times, this conversion can result in even more toxic and active products. The study of the pesticides persistence in crops is of great importance in order to evaluate the risks of environmental contamination. In this study, an analytical method for the residual determination of the insecticide carbofuran and the herbicide quinclorac in the water of irrigated rice farming, using SPE and HPLC-DAD, was developed and validated. The method consists of the pre-concentration of the water samples in SPE cartridges with 500 mg of C18 followed by elution with methanol. The extracts were analyzed by HPLC-DAD with a Gemini C18 column and detection at 220 nm for carbofuran and 270 nm for quinclorac. In the method validation, LOD, LOQ, linearity, precision (repeatability and intermediate precision) and accuracy (from the recovery) were evaluated. The LOQ values for the method were 2 μg L-1 for carbofuran and 0.6 μg L-1 for quinclorac. The analytical curves presented linearity between 0.5 and 10.0 mg L-1 for carbofuran and 0.05 and 10.0 mg L-1 for quinclorac, with coefficient of determination values higher than 0.995. The method presented good precision, with RSD values lower than 17.1%, and good accuracy, with recoveries between 82 and 112%. The detection by diode array allowed an adequate confirmation and quantification of the pesticides in study. After validation, the method was applied to analyze samples of water from irrigated rice crops from an experiment carried out at the Campus of the UFSM, where the pesticides, carbofuran and quinclorac, were applied, separately, in the 2006/2007 harvests. The herbicide quinclorac presented greater persistence, with a half life time of approximately 12 days, and residues were found up to 42 days after the application. The insecticide carbofuran was well less persistent, observing residues only up to 5 days after application. For carbofuran, it was not possible to determine the half life time and its metabolite, 3-hydroxycarbofuran, was not found in the samples analyzed.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico

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Cadmium is a toxic element even at low concentration and is no essential for human metabolism, while Mn is essential and no toxic at low concentration. For that reason, it is important to have sensitive and accurate methods for determining these elements, mainly in feeds and foodstuffs used in human nutrition. These elements may usually be found as contaminants in phosphate-base-chemicals (mainly in Tripoli phosphates), whose Cd and Mn concentrations depend on the source where the chemical is from. However, serious matrix interference is found in the determination of Cd and Mn by means of atomic spectrometry techniques. Several techniques are nowadays available for the determination of Mn and Cd, including flame atomic absorption spectrometry (FAAS), which is widespread used and usually available in laboratories, due to its relative low cost, simplicity, good sample throughput, robustness, precision and accuracy. Nevertheless, in some cases sensitivity and matrix interference may hinder FAAS employment for the determination of trace elements like Mn and Cd, being matrix separation/analyte pre concentration mandatory. Due to these facts, in this work a flow injection system (FI) coupled with solid phase extraction (SPE) was developed for Cd and Mn pre concentration/phosphate-base- matrix separation and analyte detection by means of FAAS. In order to carry out Mn and Cd pre concentration and detection with the developed FI-SPE-FAAS system a small column filled with circa 30 mg de 8-hidroxyquinoline immobilized on controlled pore glass (CPG-8-HQ) was used. Parameters like sample solution pH, solution flow rate, time of analyte pre concentration, sample volume and eluate concentration were evaluated for method development. Using the selected conditions for the FI-SPE-FAAS system operation it was possible to achieve detection limits of 7,6 ng g-1 Cd and 76 ng g-1 Mn, respectively, while the quantification limits were 25 ng g-1 Cd and 255 ng g-1 Mn, respectively. The enhancing factor was 17 for Cd and 21 for Mn when 5 mL of sample solution was processed, while the sample throughput was 24 h-1. Even doing matrix separation, the use of standard addition calibration was necessary for accurate determination of both elements. It was concluded that the proposed method could be used for the determination of Cd and Mn in phosphate-basefoodstuff used in human nutrition, which matrix interference is severe in FAAS.

Native species of the flora from South Brazil are the aim of the research of the Núcleo de Pesquisa de Produtos Naturais of Federal University of Santa Maria, Brazil. One of the most studied families is the Sterculiaceae and, in that family, there is the Waltheria douradinha Saint Hilaire specie, study purpose of this master degree work. W. douradinha, popularly known as douradinha do campo , is used to treat lung infections, cystitis, chronic ulcer and to wash syphilitic wounds. Secondary metabolites isolated from the bark of the roots from this specie, among the amide (O)-metiltembamide, three known quinolone alkaloids, Antidesmone, Waltherione-A and Waltherione-B, two cyclopeptide alkaloids also known, Waltherine-A and Chamaedrine, and a new quinolone alkaloid VG8. The structures of these substances are determined, principally, by spectroscopics methods, like Nuclear Magnetic Resonance 1H and 13 C (COSY, HMQC e HMBC), mass spectrometry and by the comparison with melting point and literature data. The alkaloids Waltherione-A (WA) and Waltherione-B (WB) are crystallized and analyzed by X-Ray Diffraction to determine their relative stereochemistries. The extracts obtained from several parts of W. douradinha, the fractions obtained from the division of the crude extract of the root and the pure alkaloids, Waltherine-A, VG8, WA, WB and their derivatives were submitted to microbiologic assays (fungus and Gram-positive and Gram-negative bacteria) by bioautography method and by Minimum Inhibitory Concentration (MIC). The alkaloid VG8 was the most active upon the tested microorganisms, with a positive result of inhibition with 0.5 μg by bioautography assay and with 50 μg mL-1 by MIC assay.

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To assist the growing nutritious demand, caused by the great population increase, the use of pesticides has been intensified in the agriculture. Such products improve the agricultural productivity and could reduce the food prices. On the other hand, starting from the results of studies of toxicological, carcinogenic and teratogenic effects of the pesticides and of the raw material used in their production, more and more rigid control parameters have been established, in the order of micro- to picogram per liter of water or per kilogram of soil or food. The control of these substances in the water requests fast, cheap and reliable analytical procedures that allow the determination of a great variety of pesticides and related compounds, with varied chemical properties and belonging to different chemical classes. In the present work it has been developed and validated a procedure for quantification of 4-chloro- α,α,α- trifluoro-toluene, o-xylene, m-xylene, p-xylene, 4-chloro-toluene, 3,4-dichloro- α,α,α- trifluoro-toluene, 4-chloro-3-nitro-α,α,α-trifluoro-toluene, 2,2-dichloroethenol-dimetyl-phosphate, trichlorfon, 3,4-dichlorophenyl isocianate, diuron, 4-chloro-3,5-dinitro-α,α,α- trifluoro-toluene, 3,4-dichloroaniline, 1-(4-Chlorophenyl)-4,4-dimethyl-3-pentanone, trifluralin, 2-[2-(4-Chlorophenyl)ethyl]-2-(1,1-dimethyl-ethyl)-oxirane, lindane, propanil, 2,4-D ester (Butyl, 2,4-dichlorophenoxi-acetate), chlorpyrifos, 2-bromomethyl-2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolane), α-endosulfan and β-endosulfan in treated industrial effluent and surface water samples using the Solid Phase Extraction (SPE), for extraction and pre-concentration, and Gas Chromatography coupled to Mass Spectrometry/Mass Spectrometry (GC-MS/MS) for the quantification. In SPE, cartridges containing a polymer with lipophilic and hydrophilic characteristics have been used, with capacity for extraction of acid and basic compounds (Abselut NEXUS, Varian). The chromatographic separation conditions were: analytical column VF - 5ms of low bleeding (Factor Four, Varian) of 30 m x 0.25 mm; 0.25 mm); carrier gas: helium, flow-rate 1.2 mL min-1; injected volume: 1 μL (splitless); programming of the column oven temperature: 45 °C 1.5 min, 260 °C (10 °C min-1) - 4 min; detector: mass spectrometer, ion trap type operating in the MS/MS way, multisegment; temperatures: transfer line: 290 °C, manifold: 80 °C and ion trap: 240 °C. In the validation of the procedure, the following parameters were appraised: detection limit (LOD), quantification limit (LOQ), linearity, precision (repeatability and intermediate precision) and recovery. The LODs obtained with the procedure were between 0.07 and 0.78 mg L-1 and the LOQs were between 0.21 and 2.44 mg L-1. The precision assays supplied acceptable results with RSD values between 1.3 and 11.9%. The recoveries were from 50.0 to 155.3%. The results obtained in this work allowed the conclusion that the proposed analytic procedure is efficient and precise for the determination of 4-chlorotoluene, 4-chloro-3-nitro-α,α,α-trifluoro-toluene, 2,2-dichloroethenol-dimetylphosphate, trichlorfon, 2-[2-(4-Chlorophenyl)ethyl]-2-(1,1-dimethyl-ethyl)-oxirane, trifluralin, lindane, chlorpyrifos, 2-bromomethyl-2-(2,4-dichlorofenyl)-4-propyl-1,3-dioxolane), α-endosulfan and β-endosulfan in industrial effluent and superficial water samples. For these compounds the precision assays supplied acceptable results with RSD values between 1.3 and 10.4%. The recoveries were from 71.7 to 128.8%. The recoveries obtained for the other compounds indicate the need to optimize the procedure to allow the analysis in the whole strip of concentrations wanted.

The dialysis of the blood, within which the most applied modality is the haemodialysis, is a method thoroughly used for the treatment of the renal inadequacy. With this treatment, toxic substances accumulated in the patient´s body that have not been eliminated by the urine, are removed. The process happens as an "artificial kidney (dialyser) that is constituted of that is constituted of a group of fine capillary with semi permeable walls. The blood goes through the inside of these capillary ones and through the outside, in opposite direction, the dialysis solution (a saline solution diluted in water) passes by. The volume of water used in each haemodialysis session is about 120 L per patient. If the water used is not monitored, pollutants can have cumulative effects in the patient, as the organochloride pesticides. With this work, it was developed and validated an analytical procedure for the determination of low concentrations of five organochloride pesticides (α-endosulfan, β-endosulfan, DDE, DDT and endrin) in water, using Solid Phase Extraction for the pre-concentration and Gas Chromatography with Electron Capture Detection for the determination of the pesticides. Tests were accomplished to optimize the pre-concentration method in which cartridges of C18-E having 500 mg of adsorbent material and an eluent mixture of n-hexane:ethyl acetate (7:3, v/v) produced the best results in terms of recovery for the five analyzed pesticides, and the obtained values were between 85.4 and 114.1%, with smaller RSD than 15%. The values of LOQ in the samples were from 14 to 20 ng L-1. After the validation stage, the analysis procedure was applied in simulations of dialysis sessions accomplished in laboratory, to verify whether it happens the passage of the referred pesticides through the membranes used in the process. Dialysers with membranes of cellulose acetate and of polissulfone, which are commercially available, were evaluated. For such, samples of water distilled/deionized, fortified with the five organochloride pesticides were used. It was verified that such membranes are permeable to the referred pesticides. Although the passage of the pesticides through the membranes has happened in low levels (ng L-1), such situation should not be disregarded, since the patients submitted to this kind of treatment are also exposed to great volumes of water in each session, that are frequently repeated for long periods of time. It is also important to highlight that the organochloride pesticides are characterized for presenting cumulative effects.

A procedure for sample decomposition was proposed in this study based on sample combustion assisted by microwave radiation. Combustion is started by microwave radiation in the presence of oxygen under pressure using ammonium nitrate as an aid for ignition. The system was adapted to commercial sample preparation quartz vessels. Three models of quartz holders were evaluated, and the chosen one was suspended at the top of the vessel, being used simultaneously as a sample holder and to protect the polytetrafluorethylene cap of the vessel from the flame generated in the combustion process. Sample was pressed into a pellet and placed on a disc paper in the holder and a solution of ammonium nitrate was added in order to start the combustion. Nitric acid or water was placed inside the vessel and it was used for analytes absorption. The system was closed and placed inside a commercial microwave oven. About 3 s of microwave irradiation were necessary to start the combustion. The microwave irradiation time of the procedure was 30 s and the combustion process took about 10 s. The system was used to digestion of bovine liver and milk powder samples and furter determination of copper and zinc. Bovine liver, milk powder, non-fat milk powder and oyster tissue certified reference materials were used to evaluate the accuracy of the procedure. Good agreement for zinc was obtained from bovine liver certified reference material when microwave combustion (95 to 104%) and microwave combustion followed by reflux, were used to sample decomposition, even if water was used for absorption of analyte. For copper, the values were between 93 and 96% for microwave combustion (not followed by reflux) in samples of bovine liver and oyster tissue, when HNO3 2 mol L-1, or concentrated, was used for analyte absorption. However, for combustion followed by reflux, the agreement was 96 to 100%. Good agreement for zinc was obtained (100%) for milk powder and non-fat milk powder, when only microwave combustion was used and HNO3 concentrate was used for analyte absorption. Results from the proposed procedure were also compared to those from conventionally used procedures for biological samples decomposition, such as wet digestion in open vessels and microwave-assisted closed vessels digestion. The advantages of this procedure include the complete sample decomposition in less time than other procedures and acid consumption (acid was used as absorption solution) always lower than 2%. Another advantage is the low residual carbon content, less of 1.3% without reflux and less than 0.4% with the reflux step.

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