Caracterização de resíduo sólido formado em biodiesel de sebo bovino

Biodiesel production has increased over the last decade because of the benefits associated with this fuel, including renewability, domestic feedstock, lower toxicity, and biodegradability. From 2008, the use of beef tallow as a feedstock for biodiesel production in Brazil has increased in significance, representing the second largest source of biodiesel, after soybeans. However, the performance of biodiesel in cold weather conditions is worse than diesel because of deposition of insoluble at low temperatures, accelerating the plugging of fuel filters and injectors of the vehicle engine. Studies have been conducted on beef tallow biodiesel, mostly related to the properties of thermal and oxidative stability. However, few studies have described the nature of the precipitate formed and its influence on product quality. Research suggests that the cause of deposition is related to the nature of saturated esters and monoacylglycerols as inducing agents. This study monitored the levels of mono-, diand triacylglycerols, the oxidation stability and the cold filter plugging point (CFPP) in beef tallow biodiesel samples from two commercial producers in Brazil for a period of twelve months. Filtered precipitates were analyzed by comparative techniques of GCFID, HPLC-UV/VIS, HPLC-MS-IT-TOF and TG to verify the nature, using monopalmitin and monostearin as reference standards. The formation of precipitate reduced the levels of monoacylglycerols in the beef tallow biodiesel. GC-FID and LCMS- IT-TOF results confirmed the nature of the deposit as saturated monoacylglycerols, predominantly monostearin and monopalmitin as the second major component. Moreover the TG analysis of the residue indicated similar thermal decomposition of the reference standards. The precipitate did not affect the oxidation stability of beef tallow biodiesel and the CFPP characteristic of blends up B60. However, the presence of iron reduced significantly the oxidation stability of biodiesel

Aplicabilidade da voltametria de pulso diferencial na quantificação de ácido fólico e ácido oxálico: um método comparativo

The development of more selective and sensitive analytical methods is of great importance in different areas of knowledge, covering, for example, food, biotechnological, environmental and pharmaceutical sectors. The study aimed to employ the technique electroanalytical differential pulse voltammetry (DPV) as an innovative and promising alternative for identification and quantification of organic compounds. The organic compounds were investigated in this study oxalic acid (OA) and folic acid (FA). The electrochemical oxidation of oxalic acid has been extensively studied as a model reaction in the boundary between the organic and inorganic electrochemistry. Since the AF, an essential vitamin for cell multiplication in all tissues, which is essential for DNA synthesis. The AF has been investigated using analytical techniques, liquid chromatography and molecular absorption spectrophotometry. The results obtained during the experimental procedure indicated that the process of electrochemical oxidation of oxalic acid is strongly dependent on the nature of the anode material and the oxidation mechanism, which affects their detection. Efficient removal was observed in Ti/PbO2 anodes, graphite, BDD and Pt 90, 85, 80 and 78% respectively. It was also shown that the DPV employing glassy carbon electrode offers a fast, simple, reliable and economical way to determine the AO during the process of electrochemical oxidation. Furthermore, electroanalytical methods are more expensive than commonly used chromatographic analysis and other instrumental methods involving toxic reagents and higher cost. Compared with the classical method of titration and DPV could be a good fit, confidence intervals and detection limits confirming the applicability of electroanalytical technique for monitoring the degradation of oxalic acid. For the study of AF was investigated the electrocatalytic activity of the carbon paste electrode for identification and quantification in pharmaceutical formulations by applying the DPV. The results obtained during the experimental procedure showed an irreversible oxidation peak at 9.1 V characteristic of FA. The carbon paste sensor showed low detection limit of 5.683×10−8 mol L-1 reducing matrix effects. The spectrophotometric analysis showed lower concentrations of HF compared with those obtained by HPLC and DPV. The levels of AF were obtained according to the methodology proposed by the Brazilian Pharmacopoeia. The electroanalytical method (DPV) proposed is cheaper than GC analysis commonly used by the pharmaceutical industry. The results demonstrated the potential of these electroanalytical techniques for future applications in environmental, chemical and biological sensors

Effect of polymerization and accelerated aging on iris color stability of ocular prosthesis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of weathering and thickness on the superficial microhardness of acrylic resin and ocular button

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Alteration of blue pigment in artificial iris in ocular prosthesis: Effect of paint, drying method and artificial aging

The artificial iris is the structure responsible for the dissimulation and aesthetics of ocular prosthesis. The objective of the present study was to evaluate the color stability of artificial iris of microwaveable polymerized ocular prosthesis, as a function of paint type, drying method and accelerated aging. A total of 40 discs of microwaveable polymerized acrylic resin were fabricated, and divided according to the blue paint type ( n = 5): hydrosoluble acrylic, nitrocellulose automotive, hydrosoluble gouache and oil paints. Paints where dried either at natural or at infrared light bulb method. Each specimen was constituted of one disc in colorless acrylic resin and another colored with a basic sclera pigment. Painting was performed in one surface of one of the discs. The specimens were submitted to an artificial aging chamber under ultraviolet light, during 1008 h. A reflective spectrophotometer was used to evaluate color changes. Data were evaluated by 3-way repeated-measures ANOVA and the Tukey HSD test (alpha = 0.05). All paints suffered color alteration. The oil paint presented the highest color resistance to artificial aging regardless of drying method. (C) 2010 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Antiviral activities of plants occurring in the state of Minas Gerais, Brazil: Part 2. Screening Bignoniaceae species

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Otimização e validação de uma metodologia analítica para determinação de 1-hidroxipireno em urina de cortadores de cana-de-açúcar

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Validated high-performance liquid chromatographic method for the standardisation of Ptychopetalum olacoides Benth., Olacaceae, commercial extracts

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Caracterização anatômica e química de folhas de Jacaranda puberula (Bignoniaceae) presente na Mata Atlântica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Controle de qualidade dos extratos polares de Turnera diffusa Willd. ex Schult., Turneraceae

Este trabalho descreve o desenvolvimento de metodologia para o controle de qualidade dos extratos etanólicos e infusão de Turnera diffusa Willd. ex Schult., Turneraceae, usando como marcadores os compostos fenólicos. Essa espécie é usada popularmente como afrodisíaca e antiulcerogênica. Foram usadas técnicas cromatográficas: CLAE acoplada com detector de ultravioleta e cromatografia em camada delgada. Foram detectados flavonóides como os principais componentes da planta.

Estudo da adsorção/dessorção de 2,4-D em solos usando técnica cromatográfica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desenvolvimento e validação de método analítico para determinação simultânea de catecolaminas em órgãos reprodutores de ratos por cromatografia líquida de alta eficiência com detecção eletroquímica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determination of phenolic compounds and evaluation of antioxidant capacity of Campomanesia adamantium leaves

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Organic acid profile of commercial sour cassava starch

A presença de ácidos orgânicos no polvilho azedo, além de contribuir com aspectos como sabor e aroma, tem, conforme a literatura indica, correlação com a propriedade de expansão, que é um fator determinante no uso alimentício. Amostras de polvilho azedo foram coletadas nas Regiões Sul e Sudeste diretamente nas empresas ou no comércio. Foram preparadas para análise em cromatografia líquida de alta eficiência (CLAE), sendo que o cromatógrafo estava equipado com coluna Biorad Aminex HPX-87H para análise de ácidos orgânicos e detector refratométrico. As condições de análise envolveram o emprego da fase móvel ácido sulfúrico 0,005M, fluxo de 0,6 ml/min e temperatura da coluna de 60oC. Os ácidos quantificados foram lático (0,036 a 0,813 g/100g), acético (0 a 0,068 g/100g), propiônico (0 a 0,013 g/100g) e butírico (0 a 0,057 g/100g), presentes na fermentação natural. Os resultados revelaram grande variação entre as amostras, com diferenças mesmo dentro das Regiões. Algumas amostras apresentaram quantidades elevadas de ácidos, especialmente do ácido lático, mas nestas amostras os ácidos propiônico e butírico não foram detectados. A ausência do ácido butírico não era esperada, uma vez que esse ácido está diretamente relacionado com o aroma característico do polvilho azedo. O fato pode sugerir que a obtenção de algumas das amostras estudadas pode ter ocorrido sem o processo fermentativo natural.

Effect of weathering and thickness on roughness of acrylic resin and ocular button

Purpose: The aim of this study was to evaluate the roughness of colorless ocular button and four brands of colorless acrylic resins designed to fabricate ocular prosthesis as a function of weathering (1008 h) and different thickness (1 and 3.5 mm). Materials and methods: One-hundred-and-twenty specimens were fabricated and distributed in 12 groups. The analysis was carried out by means of digital roughness meter. Results: Data were analyzed statistically by ANOVA and Tukey test at 1% significance. The results showed that there was no statistically significant difference after the weathering period. Both the Vipi Cril acrylic resin with 3.5 mm in thickness and ocular button with 1 mm in thickness presented the lowest roughness values (0.12. Ra). Conclusion: The roughness of the acrylic resins and the ocular button was not affect by the weathering of 1008 h. However, the thickness of the specimens proved to have a major influence on roughness property. © 2010.