Lignin chemistry and topochemistry during kraft delignification of Eucalyptus globulus genotypes with contrasting pulpwood characteristics

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

Fenólicos totais, polifenoloxidade e coloração em abacate 'Hass' submetido a radiação UV-C

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ratios of UV, PAR and NIR components to global solar radiation measured at Botucatu site in Brazil

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

Migration of Tinuvin P, a UV stabilizer, from PET bottles into fatty-food simulants

Tinuvin P migration from Polyethyleneterephthalate (PET) bottles was investigated using several fatty-food simulants such as olive oil, soybean oil, n-heptane and iso-octane, at exposure conditions of 2-10 days at 40 degrees C (total immersion). The stability of several UV stabilizers (BHT, Cyasorb UV 5411, Tinuvin P, Tinuvin 326 and Tinuvin 327) in n-heptane and iso-octane was also studied. After 10 days at 40 degrees C, losses of 6% and 20% in iso-octane and n-heptane respectively, were verified for Tinuvin P. Other UV stabilizers at the same experimental conditions showed higher losses (up to 30% for Tinuvin 327). These results confirm that, when carrying out specific migration studies, the stability of the substance of interest should be established in the food simulant to avoid underestimating the real migration behaviour. In order to quantify UV stabilizer migration, n-heptane and iso-octane solutions were concentrated and directly analysed by SIM mode GC-MS. For olive and soybean oils, Tinuvin P was isolated using size-exclusion chromatography and quantified by SIM mode GC-MS. Iso-octane proved to be a move suitable fatty-food simulant than n-heptane for the migration study of Tinuvin P from PET. Higher levels of Tinuvin P migrated to olive and soybean oils rather than to n-heptane. These results suggest that the MERCOSUL recommended official methods for specific migration studies should be revised since the migration levels using n-heptane as a fatty-food simulant could be underestimated when compared to edible oils. Copyright (C) 1999 John Wiley & Sons, Ltd.

Development and Validation of an UV-Derivative Spectrophotometric Method for Determination of Glimepiride in Tablets

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

Rapid and Selective UV Spectrophotometric Method for the Analysis of Ceftazidime

A new UV spectrophotometric method was developed for quantitative evaluation of ceftazidime preparations. The UV detector was set at 255 nm. Beer's law is obeyed in the concentration range of 7.0-14.0 mu g/mL. The method was found to be selective, linear, accurate, and precise in the specified ranges. Intra- and interday variability for the method were <2% relative standard deviation. Common excipients used as additives in pharmaceutical preparations do not interfere with the proposed method. This method was successfully used for quantification of ceftazidime in pure form and in pharmaceutical preparations.

Development and Validation of a UV-Spectrophotometric Method for Determination of Flucloxacillin Sodium in Capsules

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparative study of analytical methods by direct and first-derivative UV spectrophotometry for evaluation of losartan potassium in capsules

O losartano potássico é um agente anti-hipertensivo não peptídico, que exerce sua ação por bloqueio específico dos receptores da angiotensina II. Este trabalho propôs a validação e aplicação de métodos analíticos orientados ao controle de qualidade de losartano potássico 50 mg na forma farmacêutica cápsula, utilizando a espectrofotometria direta e derivada de primeira ordem na região do UV. Baseado nas características espectrofotométricas de losartano potássico, um sinal a 205 nm do espectro de ordem zero e um sinal a 234 nm do espectro de primeira derivada foram adequados para a quantificação. Os resultados foram usados para comparar essas duas técnicas instrumentais. O coeficiente de correlação entre as respostas e as concentrações de losartano potássico na faixa de 3,0-7,0 mg L-1 e 6,0-14,0 mg L-1 para espectrofotometria direta e derivada de primeira ordem em solução aquosa, respectivamente, foi de (r) of 0,9999 para ambos os casos. Os métodos foram aplicados para quantificação de losartano potássico em cápsulas obtidas de farmácias de manipulação locais e demonstraram ser eficientes, fáceis de aplicar e de baixo custo. Além disso, não necessitam de reagentes poluentes e requerem equipamentos economicamente viáveis.

Performance characteristics of bioassay UV-spectrophotometry and high perfomance liquid chromatographic determination of gatifloxacin in tablets

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Validação de método analítico por espectrofotometria UV para sistema emulsionado lipídico contendo benznidazol

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Performance characteristics of high performance liquid chromatography, first order derivative UV spectrophotometry and bioassay for fluconazole determination in capsules

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

Semipreparative enantioseparation of methamidophos by HPLC-UV and preliminary in vitro study of butyrylcholinesterase inhibition

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

UV exposure of polymeric geomembranes

The break of polymer chemical bonds may occur due to penetration of sun short wavelengths. In sanitary landfills for instance, ultraviolet radiation affects uncovered materials and can be dangerous during the installation of the liner and before the placement of the waste. Only the ultraviolet part of the light is harmful to the geosynthetic materials, moreover, each material is sensitive to a particular wavelength. This article evaluates the effects of UV degradation and condensation in black HDPE (1.0 and 1.5 mm) and white HDPE (textured - 1.0 mm) geomembrane that were tested in laboratory during 6 months. The tests were performed using a weatherometer assembled at EESC-USP in accordance to ASTM G154. The results have shown variations in punction and tear resistance after each period of exposure.

Evaluation of geomembrane UV degradation using melt flow index and oxidative induction time tests

Many factors such as the sunlight, intensity of radiation, temperature, and moisture may influence the degradation process of geosynthetics. UV stabilizers are used especially in polyolefin geomembrane to prevent the degradation process. In these geomembranes the service lifetime is initially governed by the consumption of antioxidants. Tests like MFI and OIT are a alternative to detect the oxidative degradation in polyolefins. This article evaluates HDPE geomembrane degradation after UV exposure through the results of MFI and OIT tests. Two kinds of geomembranes were evaluated: a black and smooth (0.8, 1.0, 1.5, 2.5 mm) and a white and textured (1.0 mm). MFI test showed some levels of superficial degradation (crosslink) in HDPE geomembrane.

Dosimetric properties of UV irradiated calcium co-doped borate glass-ceramic

The thermoluminescence (TL) response of Dy and Li doped 20CaB(4)O(7)-80CaB(2)O(4) (Wt%) glass-ceramic irradiated with ultraviolet (UV) radiation was studied. In order to act as TL activator ions, the Dy and Li ions were included in the matrix during the melting process to increase its TL efficiency. A single crystalline CaB2O4 phase was present in the glass-ceramic as determined by X-ray diffraction (XRD). The glass-ceramic 20CaB(4)O(7)-80CaB(2)O(4):Dy,Li wt% (named 20CBO7:Dy,Li) is a newly prepared TL material. Its thermoluminescent dosimetric characteristics have shown a linear response under UV radiation exposure and a good TL signal reproducibility, thus proving to be a promising material for using as an ultraviolet radiation dosimeter. (C) 2007 Elsevier B.V. All rights reserved.