The influence of high ionic strength on the potentiometric determination of pH 4.0 (25 °c, I = 1.0 mol L-1) in acidified brine of preserved hearts of palm

The aim of this study was to evaluate the influence of ionic strength (I) on the potentiometric pH measurement of solutions with high I such as the Acidified Brine of Preserved Hearts of Palm (ABPHP) as it is accurately measured only in dilute solutions where I £ 0.1 mol L-1 as defined by Debye-Hückel's theory. Standard calibrators were developed to evaluate a potassium biphthalate buffer solution (BS4: pH 4.0 at 25 °C) with the variation of I of the medium. In practical application, the objective is the optimization of the potentiometric pH measurements of solutions having high I, for example, ABPHP with an I of 0.98 mol L-1 (1). The choice of this procedure is justified because ABPHP has a naturally high I that is not consistent with Debye-Hückel's theory. This can make pH measurements unreliable. From a public health point of view, the botulism often implicated these preserved vegetables, and the potentiometric pH measurement is the only legal parameter for quality control employed to improve sanitary control actions. The quantitative variables (position and dispersion) were calculated as mean, maximum and minimum values, standard deviation and coefficient of variation. Moreover, the Grubbs’ test was used to identify possible outliers and their homogeneity, thereby demonstrating the linear tendency of the results. Student's t-test and ANOVA with a 95% confidence index were used to verify the variability of the results. The results are promising, since by altering the I of the medium (I > 0.1 mol L-1), there was a change in the pH of the solution. This study is important to ensure a true quality control in the production of preserved hearts of palm

Estimativa do cálculo da incerteza otimizada utilizando curva de adição cumulativa de padrão na determinação espectrofotométrica de nitratos em água mineral envasada

Nos últimos anos observou-se um interesse crescente na determinação dos níveis de nitrato em produtos alimentícios, essencialmente devido ao potencial de redução de nitrato em nitrito, que é conhecido por ter efeitos adversos na saúde humana e animal. O nitrato é intermediário no ciclo do nitrogênio e sua alta concentração na água é indicador de baixa qualidade (Wang et al.). A determinação direta em águas é realizada na região do ultravioleta em meio ácido e no comprimento de onda específico (205 nm) (APHA, 2012). Esse procedimento é muito útil em águas potáveis, mas suscetível a efeito de matriz em águas com pH alcalino ou com elevada força iônica (APHA, 2012). Assim, propôs-se no presente trabalho utilizar o método de adição de padrão (MAP) em comparação com o procedimento de calibração convencional (MC) descrito no livro de normas “Métodos Físico-químicos para Análise de Alimentos” (técnica 195/IV) (IAL, 2008) e executado no Laboratório de Análises Físico-químicas do Instituto Adolfo Lutz - Centro de Laboratório Regional de São José do Rio Preto X, em contrapondo, ao procedimento de adições cumulativas do padrão (MAP-C). Diante disso, foi realizada uma comparação entre os métodos MC, MAP e MAP-C, objetivando viabilizar e validar um tratamento de dados diferente do original para a estimativa do cálculo da incerteza, destacando para esse fim a abordagem bottom-up. Além, de identificar as limitações dos métodos que podem ser empregados para a vigilância da qualidade da água mineral e de abastecimento. De acordo com a ABNT NBR ISO/IEC 17025:20175, foram determinados os parâmetros de desempenho para os três procedimentos: limite de detecção, limite de quantificação, exatidão, precisão intermediária e a incerteza. Para a execução dos ensaios as condições ambientais foram monitoradas e estabelecidas as curvas de calibração (absorbância x concentração da solução padrão de nitrato de sódio, 9,98 mg L-1, calculado em N, para MC, MAP e para o MAP-C uma solução de 2,00 mg L-1), com o objetivo de determinar a concentração de nitrato de sódio. Assim, foram ensaiados 100 mL provenientes de 4L das amostras de água mineral de três marcas com diferentes pH (8,44; 6,96; e 5,77). Os parâmetros de desempenho dos procedimentos foram determinados a partir de diluições das soluções padrão e os resultados obtidos

β-galactosidase immobilization on controlled pore silica

The immobilization of β-galactosidase from Kluyveromyces fragilis on controlled pore silica was investigated. Immobilization was performed on amino silica activated with glutaraldehyde and the product was applied to the hydrolysis of lactose of whey. The behaviors of the soluble and immobilized enzyme were compared by using whey and a lactose solution as the substrate. With the aim of optimizing the method, parameters such as the amount of glutaraldehyde and the size of the particles were evaluated by comparing activities and stabilities on batch and continuously fluidized bed reactors.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Use of virtual labs for enhance student's procedimental ability.

This article presents some results of a study investigating the use of the simulator VLAB, developed by Carnegie Mellon University, to increase the capacity of graduate students in Chemistry in the preparation of experimental procedures. The activity was conducted in two stages, first the students were asked a manuscript describing in detail the procedure and equipment used in the technique of dissolution and delivering it to the teacher. Later in the computer lab, each student performed the same procedure using the simulator. The activity has been proposed to determine if there could be accuracy gains of the description of the process when performed by the simulator. One of the main positive aspects obtained using the simulator students was the recognition of error, important in that the great majority recognized omitted or confused any process step. This reflection showed the students that in addition to testing a procedure using the simulator facilitates the organization of thought and helps arrange it logically. With the use of simulators, students are encouraged to take risks, to explore, to experience a new way, and a real lab usually offers much less room for risk, exploitation and failure

Implantação do sistema ISO 9001:2000 no Laboratório de Entomologia Geral do Instituto Biológico, SP

The insect (Arthropoda, Insecta) identification and the determination if the species is exotic or quarantine are crucial for the implementation of phytosanitary measures that guarantee the productivity and competitiveness of Brazilian commodities related to food and agribusiness. In the State of São Paulo, the institution responsible for providing reports and diagnostics that will support actions of phytosanitary defense is the Instituto Biológico (IB) that has incorporated this activity in its mission: “Development and transferring of the scientific and technological knowledge to the agribusiness in the areas of animal and plant health, and their relationships with the environment, aiming and improving the life quality”. The Laboratório de Entomologia Geral (LEG) helps the IB fulfill its mission through the identification of insects, which is made with the aid of the Coleção Entomológica “Adolph Hempel” (CEAH) that contains approximately 300,000 specimens. The Ministério da Agricultura, Pecuária e Abastecimento (MAPA), is the organization in charge of implementation of food safety policy and monitoring the application of plant health legislation in Brazil. For that the MAPA uses the services of accredited laboratories that follow quality norms and standards for performance analyses. Seeking to meet the MAPA demands and giving visibility, traceability and credibility to the services provided by CEAH and LEG, it was started, in 2007, the ISO certification procedures with the implementation of 5S. In 2009 the LEG obtained the certification to ISO 9001:2000 for the scope “identification of insects and curatorship of entomological collection”. It is noteworthy that the correct identification is essential for the choice of management strategy and will be decisive in the acceptance or rejection of imported food and agricultural commodities; the latter option implies in the destruction or return of merchandise the origin resulting in losses. Thus the certification achieved for LEG ensures the quality and process safety, traceability and allows cross-checking, and underlies appropriate decisions in agribusiness.A identificação de insetos (Arthropoda, Insecta) e a determinação trata-se de espécie quarentenária ou exótica, é de importância fundamental para o cumprimento das normas fitossanitárias e é garantia de produtividade e competitividade das commodities ligadas a alimentos e dos produtos vegetais do Brasil. No Estado de São Paulo, a instituição encarregada da defesa fitossanitária é o Instituto Biológico (IB) que tem essa atividade incorporada em sua missão: “Desenvolver e transferir conhecimento científico e tecnológico para o negócio agrícola nas áreas de sanidade animal e vegetal e suas relações com o meio ambiente, visando à melhoria da qualidade de vida da população”. No Laboratório de Entomologia Geral (LEG) o cumprimento da missão do IB dá- -se por meio de uma de suas atribuições, a identificação de insetos, que é feita com o auxílio da Coleção Entomológica “Adolph Hempel” (CEAH) com, aproximadamente, 300.000 espécimes. O Ministério da Agricultura, Pecuária e Abastecimento (MAPA), responsável pela execução da política de sanidade, e aplicação e fiscalização da legislação fitossanitária no Brasil, utiliza serviços de laboratórios credenciados que sigam normas e padrões de qualidade para execução de análises entomológicas de sementes e/ou partes vegetais provenientes do exterior. Buscando atender ao MAPA e para dar visibilidade, rastreabilidade e credibilidade a prestação de serviços e a CEAH, iniciou-se em 2007 o processo de certificação na ISO com a execução do programa 5S no LEG. Em 2009 o laboratório obteve certificação na ISO 9001:2000 para o escopo “identificação de insetos e curadoria de coleção entomológica”. Vale ressaltar que a identificação correta é primordial para a escolha da estratégia de manejo a ser utilizada nas culturas, no aceite ou rejeição e consequente destruição ou devolução, pelo MAPA, de material importado e impede a entrada de pragas que podem acarretar prejuízos de milhões de reais ao Brasil. Assim sendo, o escopo para o qual o LEG foi certificado garante a qualidade e segurança do processo, permite rastreabilidade e cruzamento de informações, e embasa decisões adequadas na área da fitossanidade. Por outro lado, a certifica- ção global da coleção é complexa e só foi obtida para parte de Formicidae (Insecta, Hymenoptera) conhecida comumente como formigas

Gestão da qualidade total: introdução dos conceitos e a sua utilização em um curso para abordar o comportamento individual do aluno/profissional/cidadão

A introdução do assunto qualidade, segundo as necessidades de mercado abre espaço para a discussão da qualidade como necessidade pessoal, e também para a formação do cidadão/profissional, além de introduzir assuntos específicos de administração de empresas. Dessa forma, foi oferecida uma disciplina optativa para os alunos do Instituto de Química do Campus de Araraquara, abordando o tema Qualidade e foi denominada Gestão da Qualidade por três anos seguidos. da avaliação geral do curso extraiu-se que ele deveria ser realizado sempre, que o tema é atual e relevante e contribui para a formação profissional/pessoal. Com relação ao comprometimento com o curso de graduação, cerca de metade dos alunos assume o seu comprometimento com os estudos e os restantes dizem estarem somente envolvidos. Conclui-se, portanto que o curso atingiu os seus objetivos propostos, introduziu os principais conceitos de qualidade segundo as normas da qualidade da série ISO 9000 e suscitou a discussão da formação do aluno/profissional/cidadão.The introduction of the subject quality, according to the market needs opens space for the discussion of the quality as personal need, and also for the professional citizen's formation, besides introducing specific subjects of administration of companies. In that way, an optional discipline was offered for the students of the Chemistry Institute, approaching the theme Quality and Administration of the Quality , by three followed years. of the general evaluation of the course it was extracted that it should always be accomplished, that the theme is current and important and it contributes to the personal/professional formation. With relationship to the compromising with the degree course, about of the students' half it assumes your compromising with the studies and the remaining ones say they are only involved. It is ended, therefore that the course reached your proposed objectives, it introduced the principal quality concepts according to the norms of the quality of the series ISO 9000 and it raised the discussion of the student's professional - citizen formation

Thermal characterization of lignocellulosic residue from different sugarcanes

Bagasse samples from four different sugarcane were directly collected as the residues of milling in a processing plant. The samples were dried at 105 A degrees C, compressed to small granules and then their TG/DTA and DSC curves in synthetic air were recorded. Similar thermogravimetric curves were obtained for the different samples and they exhibited four mass loss steps. However, the analysis of the exotherm DSC peaks showed that the oxidation of the organic matter resulted different enthalpy values (Delta H/kJ g(-1)).Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Chemical and morpho-structural characterization of atmospheric aerosol (PM10 and PM2.5) in a city of São Paulo state, Brazil

To access the sources of air pollutants is crucial to control atmospheric pollution in urban areas, minimizing human exposure. Particulate matter is a pollutant of great concern making its chemical and morpho-structural characterization of enormous importance. The present work aims at the characterization of atmospheric PM10 and PM2.5. Data of the aerosol mass concentration was correlated bymultivariate analysis with water-soluble ion fraction composition accessed by ion chromatography (IC), as well as with meteorological information and air mass backward trajectories. The gravimetric analysis presented average values 3 to 4 times higher than the guide values recommended by the World Health Organization (WHO). A morpho-structural analysis by SEM/FEG coupled to EDS was also carried out identifying the coarse fraction elements from minerals and from soil resuspension organic spherical particles that originated from combustion processes as well as Ti, associated with long-distance transportation. In the fine fraction, Zn with origin probably in tires and vehicle brakes was found. These origins were confirmed by the air masses’ backward trajectories obtained by the HYSPLIT model (NOAA). This study contributes to a better understanding of the complex composition of the particulate material in the atmosphere of Araraquara City, resulting from the combination of local and long-distance sources, and serves as a basis for the comparison with future studies related to the air quality at this and other regions in Brazil and in the world.info:eu-repo/semantics/publishedVersio

HPLC-DAD method for metabolic fingerprinting of the phenotyping of sugarcane genotypes

Metabolite profiling techniques play an important role in the phenotyping and diagnostic analysis of plants. The complexity of the plant metabolome makes the application of a single extraction and analytical method to all the metabolites challenging. High performance liquid chromatography coupled to a diode array detector (HPLC-DAD) has been the most popular analytical technique for analyzing natural products. Therefore, our group aimed to develop relevant methods using experimental design techniques using the number of metabolites detectable by HPLC-DAD as a response to compare sugarcane genotypes. Using this approach, the best extraction parameters were identified, including the number of extractions and the ratios of the solvents water/ethanol/isopropanol. Chromatographic performance was optimized using a Kinetex column, methanol as solvent B and a gradient time of 60 minutes. The method was applied to the phenotyping of two sugarcane genotypes with different susceptibilities to orange rust disease. Metabolic fingerprinting was subjected to principal component analysis (PCA), enabling the discrimination of the genotypes based on their flavonoid contents.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES