É proposto um método para a determinação de fluoreto em carvão mineral. O mesmo é baseado no emprego da pirohidrólise para a separação do fluoreto da amostra e posterior determinação do analito por potenciometria direta, com eletrodo íon seletivo. O sistema utilizado para a realização da pirohidrólise foi desenvolvido e a influência do V 2 O 5 como catalisador na reação de pirohidrólise foi investigada, sendo verificado que o mesmo não influencia sobre a liberação do fluoreto presente na amostra. Amostras certificadas e não certificadas de carvão mineral foram analisadas. Resultados precisos (desvio padrão relativo inferior a 7%) e exatos (recuperação do fluoreto de acordo com os valores certificados) foram obtidos. O limite de quantificação (LOQ) do método foi de 5,0 µgF/g de amostra, usando 20 mg de amostra e volume final de 10 mL. A freqüência de análise foi de 5 amostras h -1 .A method for the determination of fluoride in coal using pyrohydrolysis for sample decomposition is proposed. An apparatus was constructed, and the influence of vanadium pentoxide (V 2 O 5 ) as a catalyst for the pyrohydrolysis reaction was investigated. It was verified that V 2 O 5 does not influence the release of fluoride from coal. Certified and non-certified samples were analysed using an ion selective electrode (ISE) for analyte detection. Precise (RSD < 7%) and accurate (recovery in accordance with certified values) results were obtained. The limit of quantification (LOQ) of the method was 5.0 µgF/g of sample, using 20 mg of sample and a final dilution to 10 mL. The sample frequency was 5 samples h -1 .Keywords: coal, fluoride, pyrohydrolysis, ion electrode, vanadium pentoxide, catalyst IntroductionFluorine is one of several trace elements receiving much attention owing to its possible harmful ecological effects. This element is considered essential to both plant and animal life at low concentrations but is toxic at high concentrations. The potential toxicity of fluorine has been classified as "high" for terrestrial life and "low" for aquatic life. 1,2 Due to the high volatility of the element, the widespread world consumption of coal may result in significant fluorine emissions. 2 From this point of view, it is important to establish accurate, precise and rapid methods for determination of this element.With the exception of a few instrumental methods, 2,3 the determination of fluoride in coal is carried out after sample dissolution. Most published methods related to the determination of fluoride in solid samples thus involve distillation, pyrohydrolysis, alkaline fusion, combustion bomb or acid decomposition in a bomb, typically followed by spectrophotometric or potentiometric measurements. 3,4 In some instances, these methods are complex and time consuming (mainly methods based on distillation and fusion), may give incomplete breakdown of fluorinecontaining compounds, analyte losses during the depressurisation of the bomb (decomposition in a combustion bomb), or by volatilisation (alkaline fusion), if the fusion temperature is...

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The aim of this study was to investigate the influence of the addition of prebiotics rice bran, inulin and hi-maize, on the survival of Lactobacillus acidophilus in alginate microparticles obtained by external ionic gelation followed by freeze-drying. The microparticles size ranged from 127.5μm to 234.6μm. Microparticles added from the different prebiotics demonstrated an increase in the protection of the microorganism, which presented greater viability against the gastrointestinal simulation. As for storage under different conditions, rice bran treatment at 25ºC kept probiotics viable for 30 days. Under storage conditions -18°C and 7°C, treatments containing prebiotics hi-maize and rice bran maintained viable probiotic microorganisms for a period of 60 days.

Um método para determinação simultânea de ácido clavulânico (CA) e amoxicilina (AMO) foi desenvolvido utilizando a técnica de espectroscopia no infravermelho médio com transformada de Fourier acoplada ao acessório de reflexão total atenuada (ATR/FTIR). Utilizaram-se 27 e 8 amostras para os conjuntos de calibração e previsão, respectivamente. Os modelos de calibração foram desenvolvidos utilizando os algoritmos por mínimos quadrados parciais (PLS), PLS por intervalo (iPLS), PLS por sinergismo (siPLS) e PLS por exclusão (biPLS). Os melhores modelos foram aqueles que utilizaram o algoritmo biPLS. Obtiveram-se erro padrão relativo de previsão (RSEP) de 3,8 e 5,1% para CA e AMO, respectivamente. Os resultados obtidos pela metodologia proposta foram comparados com os obtidos por cromatografia líquida de alta eficiência (HPLC) e nenhuma diferença significativa foi observada. O método proposto utilizando ATR/FTIR associado a métodos de análise multivariados foi satisfatório para determinação de CA e AMO em produtos farmacêuticos.A method for simultaneous determination of clavulanic acid (CA) and amoxicillin (AMO) was developed using Fourier transform mid infrared technique coupled with attenuated total reflectance (ATR/FTIR) accessory. 27 samples were used as calibration set and 8 samples were used for prediction set. Calibration models were developed using partial least squares (PLS), interval PLS (iPLS), synergy PLS (siPLS) and backward PLS (biPLS). Multiplicative scatter correction and the mean centering were used and produced the best models. Relative standard error of prediction (RSEP) of 3.8% for CA and 5.1% for AMO were obtained using biPLS algorithm for ATR/FTIR data. Results obtained by the proposed methodology were compared with those using high performance liquid chromatography (HPLC) and no significant differences were obtained. The proposed method using ATR/FTIR combined to multivariate analysis methods was suitable for the simultaneous determination of CA and AMO in commercial pharmaceutical products.

A combustão iniciada com micro-ondas (MIC) foi aplicada para decomposição de amostras de tabaco de cigarro e subsequente determinação de bromo e cloro por espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES). Massas de amostra de até 500 mg foram decompostas em frascos fechados e pressurizados com 20 bar de oxigênio. A combustão foi completada em menos de 30 s e os analitos foram absorvidos em solução diluída de (NH 4 ) 2 CO 3 . A exatidão foi avaliada usando materiais de referência certificados e mediante a determinação utilizando ICP-MS. A concordância foi melhor do que 98% usando 50 mmol L -1 de (NH 4 ) 2 CO 3 como solução absorvedora e 5 min de refluxo. A temperatura durante a combustão foi superior a 1400 °C e o conteúdo de carbono residual nos digeridos após MIC foi menor que 1%. Até oito amostras podem ser decompostas simultaneamente. Limites de quantificação utilizando MIC e determinação por ICP OES foram de 12 e 6 µg g -1 para Br e Cl, respectivamente.The microwave-induced combustion (MIC) was applied for cigarette tobacco samples digestion and further determination of bromine and chlorine by inductively coupled plasma optical emission spectrometry (ICP OES). Samples masses up to 500 mg were combusted in closed vessels using 20 bar of oxygen. Combustion was complete in less than 30 s and analytes were absorbed in diluted (NH 4 ) 2 CO 3 solution. Accuracy was evaluated using certified reference materials with similar matrix composition and comparison with results obtained using ICP-MS. The agreement was better than 98% using 50 mmol L -1 (NH 4 ) 2 CO 3 as absorbing solution and 5 min of reflux. Temperature during combustion was higher than 1400 °C and the residual carbon content in digest obtained after MIC was lower than 1%. Up to eight samples could be processed simultaneously and a single absorbing solution was suitable for both Br and Cl. Limit of quantification by MIC and further ICP OES determination was 12 and 6 µg g -1 for Br and Cl, respectively.Keywords: microwave-induced combustion, cigarette, bromine, chlorine, ICP OES IntroductionTobacco leaves may be used in different forms such as smoking, chewing or sniffing. All of these forms result in a number of negative side effects on human health that are well-documented.1 Chlorine and bromine are essential for growth of the plants and minor constituents of tobacco. The content of bromine and chlorine in tobacco could vary depending on tobacco type, soil and climatic conditions. Typical concentration ranges for Br and Cl reported in tobacco are 100 to 200 and 700 to 30000 µg g -1 , respectively. Over 85% of the all halogenated compounds found in tobacco and smoke are either halogenated agrochemicals, impurities found in the agrochemicals, or decomposition products from the agrochemicals. Up to 2.4% of the bromine and chlorine can be transferred to smoke. There are 242 identified halogenated compounds in tobacco and/or tobacco smoke and chlorine and bromine are present in 192 and 12 different compounds, respectively. 2Bromine...

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