9 research outputs found

    Development and validation of a HPLC method for the determination of aldicarb, aldicarb sulfoxide and aldicarb sulfone in liquid samples from anaerobic reactors

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    This study describes the development and validation of a high-performance liquid chromatography (HPLC) method for detecting aldicarb and its residues in liquid samples without pretreatment. The HPLC system was equipped with a C-18 column and the mobile phase was composed of a mixture of water and acetonitrile using a linear gradient elution. The UV detector was utilized at 210 nm. Methomyl was used as an internal standard. Water and synthetic medium were used as solvents. The method was linear from 0.49-15.0 mg L-1 (r² > 0.9985), 0.1-5.0 mg L-1 (r² > 0.9974) and 0.1-5.0 mg L-1 (r² > 0.9987) for aldicarb, aldicarb sulfoxide and aldicarb sulfone, respectively. The linearity of the method was confirmed by the ANOVA F-test through adjustment of the linear model, validity of the regression and efficiency of the regression tests. The limit of detection in water and synthetic medium were of 0.391/0.440 mg L-1, 0.069/0.192 mg L-1 and 0.033/0.068 mg L-1 for aldicarb, aldicarb sulfoxide and aldicarb sulfone, respectively. Total time of analysis was of 22 min. In the application of the method, the aldicarb degradation in horizontal-flow anaerobic immobilized biomass (HAIB) reactor was evaluated under different conditions (methanogenic, sulfidogenic and denitrifying).Este trabalho descreve o desenvolvimento e validação de um método de detecção de aldicarbe e seus metabólitos por cromatografia líquida de alta eficiência (HPLC) em amostras líquidas sem pré-tratamento. O sistema HPLC foi equipado com coluna C-18 e fase móvel composta de água e acetonitrila empregando gradiente de eluição linear. O detector UV foi operado em 210 nm. Metomil foi utilizado como padrão interno. Água e meio sintético foram utilizados como solventes. O método foi linear de 0,49-15,0 mg L-1 (r² > 0,9985), 0,1-5,0 mg L-1 (r² > 0,9974) e 0,1-5,0 mg L-1 (r² > 0,9987) para o aldicarbe, sulfóxido de aldicarbe e sulfona de aldicarbe, respectivamente. A linearidade do método foi confirmada pelo teste F (ANOVA) através dos testes de ajuste do modelo linear, validade da regressão e eficiência da regressão. Os limites de detecção na água e em meio sintético foram de 0,391/0,440 mg L-1, 0,069/0,192 mg L-1 e 0,033/0,068 mg L-1 para o aldicarbe, sulfóxido de aldicarbe e sulfona de aldicarbe, respectivamente. O tempo total de análise foi de 22 minutos. Na aplicação do método, avaliou-se a degradação do aldicarbe no reator anaeróbio horizontal de leito fixo (RAHLF) em diferentes condições operacionais (metanogênese, sulfetogênese e desnitrificação).Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Bacterial diversity from environmental sample applied to bio-hydrogen production

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    Environmental from tropical climate countries as sediments in standing waters are complex habitats which are able to provide favorable living conditions for manifold microbial species. The aim of this study was to evaluate the diversity of the anaerobic bacteria present in the sediment of the reservoir and its application in biological production of hydrogen gas. The anaerobic batch reactors showed a xylose consumption of 63.5% at 72 h of operation with yield of H-2 production of 0.3 (mol H-2/mol xylose) at 37 degrees C, pH 5.5. Molecular biology techniques used for genomic DNA extraction, cloning, sequencing and phylogenetic analyses of the sediment sampling revealed clones similar to the phyla Proteobacteria, Chloroflexi, Firmicutes, Deferribacteres, Fusobacteria, Cyanobacteria and uncultured bacteria, The analysis of DGGE revealed changes in microbial populations from the sediment and the anaerobic consortia of bacteria from the reactors fed with xylose. Anaerobic bacteria coming from the sediment, mainly rods forming endospores from Phylum Firmicutes were favored by the experimental conditions imposed and they were probably involved in the biologic process of the H-2 production. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Effect of a probiotic beverage consumption (Enterococcus faecium CRL 183 and Bifidobacterium longum ATCC 15707) in rats with chemically induced colitis

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