Avaliação de um método de cromatografia em fase gasosa head space e estudo da estabilidade do etanol em amostras de sangue

The ethanol is the most overused psychoactive drug over the world; this fact makes it one of the main substances required in toxicological exams nowadays. The development of an analytical method, adaptation or implementation of a method known, involves a process of validation that estimates its efficiency in the laboratory routine and credibility of the method. The stability is defined as the ability of the sample of material to keep the initial value of a quantitative measure for a defined period within specific limits when stored under defined conditions. This study aimed to evaluate the method of Gas chromatography and study the stability of ethanol in blood samples, considering the variables time and temperature of storage, and the presence of preservative and, with that check if the conditions of conservation and storage used in this study maintain the quality of the sample and preserve the originally amount of analyte present. Blood samples were collected from 10 volunteers to evaluate the method and to study the stability of ethanol. For the evaluation of the method, part of the samples was added to known concentrations of ethanol. In the study of stability, the other side of the pool of blood was placed in two containers: one containing the preservative sodium fluoride 1% and the anticoagulant heparin and the other only heparin, was added ethanol at a concentration of 0.6 g/L, fractionated in two bottles, one being stored at 4ºC (refrigerator) and another at -20ºC (freezer), the tests were performed on the same day (time zero) and after 1, 3, 7, 14, 30 and 60 days of storage. The assessment found the difference in results during storage in relation to time zero. It used the technique of headspace associated with gas chromatography with the FID and capillary column with stationary phase of polyethylene. The best analysis of chromatographic conditions were: temperature of 50ºC (column), 150ºC (jet) and 250ºC (detector), with retention time for ethanol from 9.107 ± 0.026 and the tercbutanol (internal standard) of 8.170 ± 0.081 minutes, the ethanol being separated properly from acetaldehyde, acetone, methanol and 2-propanol, which are potential interfering in the determination of ethanol. The technique showed linearity in the concentration range of 0.01 and 3.2 g/L (0.8051 x + y = 0.6196; r2 = 0.999). The calibration curve showed the following equation of the line: y = x 0.7542 + 0.6545, with a linear correlation coefficient equal to 0.996. The average recovery was 100.2%, the coefficients of variation of accuracy and inter intra test showed values of up to 7.3%, the limit of detection and quantification was 0.01 g/L and showed coefficient of variation within the allowed. The analytical method evaluated in this study proved to be fast, efficient and practical, given the objective of this work satisfactorily. The study of stability has less than 20% difference in the response obtained under the conditions of storage and stipulated period, compared with the response obtained at time zero and at the significance level of 5%, no statistical difference in the concentration of ethanol was observed between analysis. The results reinforce the reliability of the method of gas chromatography and blood samples in search of ethanol, either in the toxicological, forensic, social or clinic

Processamento e caracterização da blenda poli (metacrilato de metila) (PMMA) elastomerico e poli (tereftalato de etileno) (PET) pós-consumo

This work studied the immiscible blend of elastomeric poly(methyl methacrylate) (PMMA) with poly(ethylene terephthalate) (PET) bottle grade with and without the use of compatibilizer agent, poly(methyl methacrylate-co-glycidyl methacrylate - co-ethyl acrylate) (MGE). The characterizations of torque rheometry, melt flow index measurement (MFI), measuring the density and the degree of cristallinity by pycnometry, tensile testing, method of work essential fracture (EWF), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were performed in pure polymer and blends PMMA/PET. The rheological results showed evidence of signs of chemical reaction between the epoxy group MGE with the end groups of the PET chains and also to the elastomeric phase of PMMA. The increase in the concentration of PET reduced torque and adding MGE increased the torque of the blend of PMMA/PET. The results of the MFI also show that elastomeric PMMA showed lower flow and thus higher viscosity than PET. In the results of picnometry observed that increasing the percentage of PET resulted in an increase in density and degree crystallinity of the blends PMMA/PET. The tensile test showed that increasing the percentage of PET resulted in an increase in ultimate strength and elastic modulus and decrease in elongation at break. However, in the phase inversion, where the blend showed evidence of a co-continuous morphology and also, with 30% PET dispersed phase and compatibilized with 5% MGE, there were significant results elongation at break compared to elastomeric PMMA. The applicability of the method of essential work of fracture was shown to be possible for most formulations. And it was observed that with increasing elastomeric PMMA in the formulations of the blends there was an improvement in specific amounts of essential work of fracture (We) and a decrease in the values of specific non-essential work of fracture (βWp)

Processamento e caracterização da blenda poli (metacrilato de metila) (PMMA) elastomerico e poli (tereftalato de etileno) (PET) pós-consumo

This work studied the immiscible blend of elastomeric poly(methyl methacrylate) (PMMA) with poly(ethylene terephthalate) (PET) bottle grade with and without the use of compatibilizer agent, poly(methyl methacrylate-co-glycidyl methacrylate - co-ethyl acrylate) (MGE). The characterizations of torque rheometry, melt flow index measurement (MFI), measuring the density and the degree of cristallinity by pycnometry, tensile testing, method of work essential fracture (EWF), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were performed in pure polymer and blends PMMA/PET. The rheological results showed evidence of signs of chemical reaction between the epoxy group MGE with the end groups of the PET chains and also to the elastomeric phase of PMMA. The increase in the concentration of PET reduced torque and adding MGE increased the torque of the blend of PMMA/PET. The results of the MFI also show that elastomeric PMMA showed lower flow and thus higher viscosity than PET. In the results of picnometry observed that increasing the percentage of PET resulted in an increase in density and degree crystallinity of the blends PMMA/PET. The tensile test showed that increasing the percentage of PET resulted in an increase in ultimate strength and elastic modulus and decrease in elongation at break. However, in the phase inversion, where the blend showed evidence of a co-continuous morphology and also, with 30% PET dispersed phase and compatibilized with 5% MGE, there were significant results elongation at break compared to elastomeric PMMA. The applicability of the method of essential work of fracture was shown to be possible for most formulations. And it was observed that with increasing elastomeric PMMA in the formulations of the blends there was an improvement in specific amounts of essential work of fracture (We) and a decrease in the values of specific non-essential work of fracture (βWp)

Emulsões de óleo de copaíba: determinação do equilíbrio hidrófilo-lipófilo crítico (EHLC), propriedades e estabilidade físico-químicas

Durante as últimas décadas, as indústrias farmacêuticas têm despertado grande interesse em óleos vegetais e vários extratos de planta por causa da sua baixa toxicidade e alta biodegrabilidade. O óleo de copaíba (Cop) é usado in natura na medicina popular como anti-inflamatório e antimicrobiano para tratar várias doenças, tais como inflamação da garganta, úlceras e infecções urinárias e pulmonares. Emulsões são sistemas dispersos termodinamicamente instáveis que consistem em dispersões de gotículas microscópicas em outro líquido imiscível. O objetivo deste trabalho foi preparar diferentes emulsões de Cop, determinar o EHL crítico deste óleo e avaliar a sua estabilidade, além de realizar estudos comparativos entre diferentes métodos de construção de diagramas de fases. As emulsões foram preparadas pelo método de inversão de fases variando as proporções de EHL de 4,7 a 16,7. A estabilidade foi determinada por vários métodos e os diagramas de fases foram produzidos pelo método de titulação usando diferentes procedimentos de agitação. As emulsões a base de Cop com EHL entre 12,7 e 15,7 foram as mais estáveis. As emulsões apresentaram boa estabilidade em curto e longo prazo, aspecto leitoso e baixos valores de índice de cremagem. Diferentes sistemas coloidais foram produzidos a partir dos diagramas de fases dependendo do processo de agitação. Baseado nesses métodos, o valor determinado de EHL do Cop foi 14,8, as emulsões permaneceram estáveis por mais de um ano e estes resultados indicam que o estudo das emulsões de Cop pode ser um promissor veículo de liberação tópica de fármacos e ativos cosméticos

Influência de fármacos lipofílicos na estabilidade de emulsões de uso terapêutico

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Estudo de uma coluna de absorção recheada para desidratação do gás natural utilizando microemulsão como absorvente

During natural gas processing, water removal is considered as a fundamental step in that combination of hydrocarbons and water favors the formation of hydrates. The gas produced in the Potiguar Basin (Brazil) presents high water content (approximately 15000 ppm) and its dehydration is achieved via absorption and adsorption operations. This process is carried out at the Gas Treatment Unit (GTU) in Guamaré (GMR), in the State of Rio Grande do Norte. However, it is a costly process, which does not provide satisfactory results when water contents as low as 0.5 ppm are required as the exit of the GTU. In view of this, microemulsions research is regarded as an alternative to natural gas dehydration activities. Microemulsions can be used as desiccant fluids because of their unique proprieties, namely solubilization enhancement, reduction in interfacial tensions and large interfacial area between continuous and dispersed phases. These are actually important parameters to ensure the efficiency of an absorption column. In this work, the formulation of the desiccant fluid was determined via phases diagram construction, employing there nonionic surfactants (RDG 60, UNTL L60 and AMD 60) and a nonpolar fluid provided by Petrobras GMR (Brazil) typically comprising low-molecular weight liquid hydrocarbons ( a solvent commonly know as aguarrás ). From the array of phases diagrams built, four representative formulations have been selected for providing better results: 30% RDG 60-70% aguarrás; 15% RDG 60-15% AMD 60-70% aguarrás, 30% UNTL L60-70% aguarrás, 15% UNTL L60-15% AMD 60-70% aguarrás. Since commercial natural gas is already processed, and therefore dehydrated, it was necessary to moister some sample prior to all assays. It was then allowed to cool down to 13ºC and interacted with wet 8-12 mesh 4A molecular sieve, thus enabling the generation of gas samples with water content (approximately 15000 ppm). The determination of the equilibrium curves was performed based on the dynamic method, which stagnated liquid phase and gas phase at a flow rate of 200 mL min-1. The hydrodynamic study was done with the aim of established the pressure drop and dynamic liquid hold-up. This investigation allowed are to set the working flow rates at 840 mL min-1 for the gas phase and 600 mLmin-1 for the liquid phase. The mass transfer study indicated that the system formed by UNTL L60- turpentine-natural gas the highest value of NUT

Aperfeiçoamento no projeto de um protótipo de misturador-decantador à inversão de fases visando aplicação na indústria do petróleo

In the oil industry the mixture oil/water occurs in the operations of production, transportation and refining, as well as during the use of its derivatives. The amount of water produced associated with the oil varies and can reach values of 90% in volume in the case of mature phase of the production fields. The present work deals with the development of new design of the Mixer Settler based on Phase Inversion (MDIF) in a laboratory scale. We envisage this application in industrial scale so the phases of project, construction and operation are considered. The modifications most significant, in comparison with the original prototype, include the materials of construction and the substitution of the equipment used in the mixing stage of the process. It was tested the viability of substitution of the original system of mechanical mixing by a static mixer. A statistical treatment by means of an experimental design of composed central type was used in order to evaluate the behavior of the main variables of the separation process as function of the efficiency of separation for the new device. This procedure is useful to delimit an optimal region of operation with the equipment. The variables of process considered on the experimental design were: oil concentration in the feeding water (mg/L); Total volumetric flow rate (L/h); Ratio organic/water on volumetric basis (O/A). The separation efficiency is calculated by comparison of the content of oil and greases in the inlet and outlet of the equipment. For determination of TOG (Total Oil and Grease), the method used was based in the absorption of radiation in the infra-red region. The equipment used for these determinations was InfraCal® TOG/TPH Model HATR-T2 of the Wilks Enterprise, Incorporation. It´s important to stand out that this method of measure has being used by PETROBRAS S.A. Results of global efficiency of separation oil/water varied from 75.3 to 97.7% for contaminated waters containing up to 1664,1 mg/L of oil. By means of tests carried out with a real sample of contaminated water supplied by PETROBRAS we have got an effluent specified in terms of the legal standards required for discharging. Thus, the new design of equipment constitutes a real alternative for the conventional systems of treatment of produced water in the oil industry

Auditoria de inteligência: um método para o diagnóstico de sistemas de inteligência competitiva e organizacional

CARVALHO, Andréa Vasconcelos ; ESTEBAN NAVARRO, Miguel Ángel. . Auditoria de Inteligência: um método para o diagnóstico de sistemas de inteligência competitiva e organizacional. In: XI ENANCIB - Encontro Nacional de Pesquisa em Ciência da Informação, 2010, Rio de Janeiro. Anais do XI ENANCIB. Rio de Janeiro: ANCIB, 2010.

Obtenção de nanopartículas de hexaferrita de bário pelo método pechini

In this study barium hexaferrite was (general formulae BaFe12O19) was synthesized by the Pechini method under different conditions of heat treatment. Precursors like barium carbonate and iron nitrate were used. These magnetic ceramic, with magnetoplumbite type structure, are widely used as permanent magnet because of its excellent magnetic properties, such as: high Curie temperature, good magnetic anisotropy, high coercivity and corrosion resistance. The samples were characterized by thermal analysis (DTA and TG), X- ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) end Vibrating sample Magnetometer (VSM). The results confirm the expected phase, which was reinforced according to our analysis. A single phase powder at relatively high temperatures with particle sizes around 100 nm was obtained. The characteristic magnetic behavior one of the phases has been noted (probably superparamagnetic material), while another phase was identified as a ferrimagnetic material. The ferrimagnetic phase showed vortex configuration with two central and slightly inclined plateaus. In general, increase of heat treatment temperature and time, directly influenced the technological properties of the samples

Obtenção e caracterização de dióxido de estanho nanoestruturado pelo método de síntese contínua por combustão em solução

Continuous Synthesis by Solution Combustion was employed in this work aiming to obtain tin dioxide nanostructured. Basically, a precursor solution is prepared and then be atomized and sprayed into the flame, where its combustion occurs, leading to the formation of particles. This is a recent technique that shows an enormous potential in oxides deposition, mainly by the low cost of equipment and precursors employed. The tin dioxide (SnO2) nanostructured has been widely used in various applications, especially as gas sensors and varistors. In the case of sensors based on semiconducting ceramics, where surface reactions are responsible for the detection of gases, the importance of surface area and particle size is even greater. The preference for a nanostructured material is based on its significant increase in surface area compared to conventional microcrystalline powders and small particle size, which may benefit certain properties such as high electrical conductivity, high thermal stability, mechanical and chemical. In this work, were employed as precursor solution tin chloride dehydrate diluted in anhydrous ethyl alcohol. Were utilized molar ratio chloride/solvent of 0,75 with the purpose of investigate its influence in the microstructure of produced powder. The solution precursor flux was 3 mL/min. Analysis with X-ray diffraction appointed that a solution precursor with molar ratio chloride/solvent of 0,75 leads to crystalline powder with single phase and all peaks are attributed to phase SnO2. Parameters as distance from the flame with atomizer distance from the capture system with the pilot, molar ratio and solution flux doesn t affect the presence of tin dioxide in the produced powder. In the characterization of the obtained powder techniques were used as thermogravimetric (TGA) and thermodiferential analysis (DTA), particle size by laser diffraction (GDL), crystallographic analysis by X-ray diffraction (XRD), morphology by scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area (BET) and electrical conductivity analysis. The techniques used revealed that the SnO2 exhibits behavior of a semiconductor material, and a potentially promising material for application as varistor and sensor systems for gas

Influência do método de síntese e caracterização de pós compósitos de NiO- Ce1-xEuxO2-δ para anodos catalíticos de células a combustível

Fuel cells are electrochemical devices that convert chemical energy into electricity. Due to the development of new materials, fuel cells are emerging as generating clean energy generator. Among the types of fuel cells, categorized according to the electrode type, the solid oxide fuel cells (SOFC) stand out due to be the only device entirely made of solid particles. Beyond that, their operation temperature is relatively high (between 500 and 1000 °C), allowing them to operate with high efficiency. Another aspect that promotes the use of SOFC over other cells is their ability to operate with different fuels. The CeO2 based materials doped with rare earth (TR+3) may be used as alternatives to traditional NiO-YSZ anodes as they have higher ionic conductivity and smaller ohmic losses compared to YSZ, and can operate at lower temperatures (500-800°C). In the composition of the anode, the concentration of NiO, acting as a catalyst in YSZ provides high electrical conductivity and high electrochemical activity of reactions, providing internal reform in the cell. In this work compounds of NiO - Ce1-xEuxO2-δ (x = 0.1, 0.2 and 0.3) were synthesized from polymeric precursor, Pechini, method of combustion and also by microwave-assisted hydrothermal method. The materials were characterized by the techniques of TG, TPR, XRD and FEG-SEM. The refinement of data obtained by X-ray diffraction showed that all powders of NiO - Cex-1EuxO2-δ crystallized in a cubic phase with fluorite structure, and also the presence of Ni. Through the characterizations can be proved that all routes of preparation used were effective for producing ceramics with characteristics suitable for application as SOFC anodes, but the microwave-assisted hydrothermal method showed a significant reduction in the average grain size and improved control of the compositions of the phases

Quantificação de Fases Cristalinas de Incrustações em Colunas de Produção de Petróleo pelo Método Rietveld

The scale is defined as chemical compounds from inorganic nature, initially soluble in salt solutions, which may precipitate accumulate in columns of production and surface equipment. This work aimd to quantify the crystalline phases of scale through the Rietveld method. The study was conducted in scale derived from columns production wells in development and recipients of pigs. After collecting samples of scale were performed the procedure for separations of inorganic and organic phase and preparation to be analyzed at the X-ray Laboratory. The XRD and XRF techniques were used to monitor whether identifying and quantifying crystalline phases present in the deposits. The SEM technique was used to visualize the morphology of the scales and assess their homogeneity after the milling process. XRD measurements were performed with and without milling and with or without the accessory spinner. For quantify crystalline phases the program DBWStools was used. The procedure for conducting the first refinement was instrumental in setting parameters, then the structural parameters of the phases in the sample and finally the parameters of the function profile used. In the diffraction patterns of samples of scale observed that the best measures were those that passed through the mill and used the accessory spinner. Through the results, it was noted that the quantitative analysis for samples of scale is feasible when need to monitor a particular crystalline phase in a well, pipeline or oil field. Routinely, the quantification of phases by the Rietveld method is hardwork because in many scale was very difficult to identify the crystalline phases present

Novo método para estimativa do gradiente de fratura para poços de petróleo

The development of oil wells drilling requires additional cares mainly if the drilling is in offshore ultra deep water with low overburden pressure gradients which cause low fracture gradients and, consequently, difficult the well drilling by the reduction of the operational window. To minimize, in the well planning phases, the difficulties faced by the drilling in those sceneries, indirect models are used to estimate fracture gradient that foresees approximate values for leakoff tests. These models generate curves of geopressures that allow detailed analysis of the pressure behavior for the whole well. Most of these models are based on the Terzaghi equation, just differentiating in the determination of the values of rock tension coefficient. This work proposes an alternative method for prediction of fracture pressure gradient based on a geometric correlation that relates the pressure gradients proportionally for a given depth and extrapolates it for the whole well depth, meaning that theses parameters vary in a fixed proportion. The model is based on the application of analytical proportion segments corresponding to the differential pressure related to the rock tension. The study shows that the proposed analytical proportion segments reaches values of fracture gradient with good agreement with those available for leakoff tests in the field area. The obtained results were compared with twelve different indirect models for fracture pressure gradient prediction based on the compacting effect. For this, a software was developed using Matlab language. The comparison was also made varying the water depth from zero (onshore wellbores) to 1500 meters. The leakoff tests are also used to compare the different methods including the one proposed in this work. The presented work gives good results for error analysis compared to other methods and, due to its simplicity, justify its possible application

Alcoolemia em vítimas fatais de acidentes de trânsito no Rio Grande do Norte empregando cromatografia em fase gasosa - head space

Alcohol is one of the few psychotropic drugs that their consumption has admitted legally and sometimes encouraged by the society. Studies show alcohol as the highest consumption of drugs among young people and society in general, probably because of its availability and easy access. The abuse causes public health problems, which was closely related to the violence, socioeconomic problems and the high number of automobile accidents. Transit is one of the main sectors affected by the effects of alcohol, observing a high incidence in the studies. About half of automobile accidents occurs after the consumption of alcoholic beverage, and the vast majority of cases related to high concentrations of alcohol in the bloodstream. The relationship of drunk with traffic accidents is in fact evident everywhere in the world, including Brazil, where studies have shown a high relationship between alcohol consumption and traffic accidents. This study determined the alcohol in fatal victims of traffic accidents in the state of Rio Grande do Norte and established the profile of this population compared with those found in Brazil and other countries. Samples of blood of ethanol added to fulfillment of the standardization of chromatographic conditions and procedures for the analysis, being employed in the determination of alcohol in blood samples of 277 victims of traffic accidents, collected at the Institute of Scientific Technical Police of Rio Grande do North (ITEP) in the year 2007. The blood alcohol level was determined in these samples correlated with the sex, age and marital status of the victim and the location, day of week and month when the accident occurred, is doing a statistical analysis and outlining a profile of the victims of an accident at transit in the state of Rio Grande do Norte. The parameters of standardization studied ensured the quality of the analytical method and, consequently, to obtain reliable laboratory results. Being given the best temperature for injector (150 ºC), detector (250 ºC) and column (50 ºC) with a flow of gas in the column of 2mL/minutos and analysis of time of 12 minutes. The method was linear in the range of 0.01 to 3.2 g / L (r2 = 0.9989) with average recovery of 100.2% and precision with coefficient of variation less than 15%. The analysis carried out on victims of fatal road traffic accidents, ethanol detected in the blood in 66.43% of the victims and these, 96% showed concentration ≥ 0.2 g / L, 87.73% of victims were male, while 12.27% female. The younger age group (1535 years) was the most involved (52,35%) and most single (55.60%). The accidents occurred with greater prevalence in the day on Monday (27%) followed by Sunday (24,19%) and Saturday (15,52%) and it was found that the prevalence of injuries varied between the different months of the year, and in February (14.4%) and April (10.47%) the months that had a higher number of accidents, however this oscillation showed no statistically significant difference. Also no significant difference was observed between the tracks of concentration found in men and women. The standardized method showed to be efficient, given satisfactorily to the goals of this work, and the high levels of alcohol found in victims of fatal road traffic accidents are consistent with several studies of literature, and the profile of the victim also supported by presenting in its most young adults, male and single

Desenvolvimento e validação de método analítico para determinação de teor de ácido gálico e catequina no fitoterápico sanativo® por cromatografia líquida de alta eficiência

The herbal medicine Sanativo® is produced by the Pernambucano Laboratory since 1888 with indications of healing and hemostasis. It is composed of a fluid extract about Piptadenia colubrina, Schinus terebinthifolius, Cereus peruvianus and Physalis angulata. Among the plants in their composition, S. terebinthifolius and P. colubrina have in common phenolic compounds which are assigned most of its pharmacological effects. The tannins, gallic acid and catechin were selected as markers for quality control. The aim of this study was the development and validation of analytical method by HPLC/UV/DAD for the separation and simultaneous quantification of gallic acid (GAC) and catechin (CTQ) in Sanativo®. The chromatographic system was to stationary phase, C-18 RP column, 4,6 x 150 mm (5 mm) under a temperature of 35 ° C, detection at 270 and 210 nm. The mobile phase consisted of 0.05% trifluoroacetic acid and methanol in the proportions 88:12 (v/v), a flow rate of 1 ml/min. The analytical method presented a retention factor of 0.30 and 1.36, tail factor of 1.8 and 1.63 for gallic acid and catechin, respectively, resolution of 18.2, and theoretical plates above 2000. The method validation parameters met the requirements of Resolution n º 899 of May 29, 2003, ANVISA. The correlation coefficient of linear regression analysis for GAC and CTQ from the standard solution was 0.9958 and 0.9973 and when performed from the Sanativo® 0.9973 and 0.9936, the matrix does not interfere in the range 70 to 110 %. The limits of detection and quantification for GAC and CQT were 3.25 and 0.863, and 9.57 and 2.55 mg/mL, respectively. The markers, GAC and CQT, showed repetibility (coefficient of variation of 0.94 % and 2.36 %) and satisfactory recovery (100.02 ± 1.11 % and 101.32 ± 1.36 %). The method has been characterized selective and robust quantification of GAC and CTQ in the Sanativo® and was considered validated