Nelson Roberto Antoniosi Filho

Estudo da estabilidade termica de oleos e gorduras vegetais por TG/DTG e DTA

Vegetal oils and fats are very useful in the food and chemist industry, they have demanded from researchers and technicians analytical methods able to estimate the conditions for their processing and storage. The thermal stability of vegetal oils is a main determinant in recognizing their value. The goal of this study is to evaluate the thermal stability of vegetable oils and fats extracted from the seeds of plants from Brazilian cerrado (araticum, babassu, Brazilian wine-palm, guariroba, murici). The thermal stability was evaluated by TG/DTG and DTA techniques, in a temperature range from 30o to 650o, under nitrogen atmosphere, and at a heating rate 10o C min-1. The TG/DTG and DTA used were efficient and fast in the determination of oils and fasts studied.

Use of feathers of feral pigeons (Columba livia) as a technique for metal quantification and environmental monitoring

This study quantifies metal concentrations in washed and unwashed feathers of feral pigeons (Columba livia). The material was collected in two different sites: Goiânia (capital of Goiás State), with high anthropic activities, and Jataí (a city in Goiás), with low anthropic activities. Results revealed that metals such as Pb, Cr, and Cd were deposited in the feathers originating from air and soil (exogenous process). Other metals such as Cu, Fe, Mn, and Zn, which are part of the tissue constitution of a living being, were absorbed through the pigeons’ diet (endogenous process). There was a statistically significant difference between mean values of Cd, Pb, and Cr in the three collection sites. The order of metal concentrations were Civic Square > Zoo > Jataí, which shows highest levels of metal contamination in anthropic environments. Significant differences between Cd, Pb, and Cr in washed and unwashed feathers suggest that metal concentrations are directly related to exposure time due to exogenous sources. We concluded that it is possible to quantify and monitor metal levels in the environment by analyzing the feathers of urban feral pigeons. Furthermore, unwashed feathers were especially efficient to investigate endogenous and exogenous absorption of the metals in our study.

Avaliação da potencialidade de microalgas dulcícolas como fonte de matéria-prima graxa para a produção de biodiesel

In this work, the fatty acid quantity and composition of six freshwater microalgae and soybean grains was determined by direct transesterification and gas chromatography analysis. The results showed that all the freshwater microalgae species presented a higher quantity of fatty acid than soybean grain. Choricystis sp. (A) provides 115% more fatty acids per gram of biomass than soybean grain. With regard to the fatty acid composition, Choricystis sp. (A) showed an adequate proportion of saturated and unsaturated fatty acids, with lower quantity of polyunsaturated fatty acids and, akin to some marine microalgae, constitutes an alternative raw material for biodiesel production.

Removal of BTEX from aqueous solution using Moringa oleifera seed cake

In this study, the removal of BTEX (benzene, toluene, ethylbenzene, p-xylene and o-xylene) from aqueous solution using Moringa oleifera seed cake (MOSC) was investigated. The effect of parameters such as contact time, pH and initial BTEX concentration were studied to optimize the conditions for maximum removal. Maximum removal values of 75±1%, 85±2%, 86±2%, 88±2% and 87±1% were obtained for benzene, toluene, ethylbenzene, p-xylene and o-xylene, respectively, at pH 7.0, with a 20 min contact time for an adsorbent dose of 10 g L−1 of 1 mg L−1 BTEX concentration. The adsorption data fitted the Langmuir and Freundlich adsorption isotherms. The capacity of MOSC to adsorb BTEX was compared with that for a commercial activated carbon. The results from the two methods were not significantly different (judged by t-test at 95% confident interval). A low cost, easy purchase and the satisfactory experimental results indicated that MOSC is a promising natural material for the removal of BTEX from aqueous solution.

Degradation of the commercial herbicide glyphosate by photo-fenton process: evaluation of kinetic parameters and toxicity

Parameters that influence the efficiency of the degradation of glyphosate (addition of Fe2+, simultaneous addition of Fe2+ and Fe3+ at a 1:1 (Fe2+/Fe3+) molar ratio, addition of oxalate and of H2O2) were evaluated at lab-scale. Synergic effects on its degradation and release of phosphate were observed using Fe2+/Fe3+, as well as adding oxalate. On the other hand, the concentration increase of Fe2+/Fe3+, oxalate and H2O2 did not promote a linear increase of glyphosate mineralization and release of phosphate. Using high concentrations of these species, the efficiency of glyphosate mineralization and release of phosphate was constant or even decreased. Under optimized conditions (0.27 mmol L-1 of Fe2+/Fe3+; 1.13 mmol L-1 of oxalate and 10.3 mmol L-1 of H2O2), close results for mineralization and release of phosphate were obtained in lab-scale and using a solar pilot plant. A direct ratio between reducing the toxicity and glyphosate concentration was also observed.

Desenvolvimento e aplicação de sistema passivo de coleta de poluentes atmosféricos para monitoramento de Cd, Cr, Pb, Cu, Fe, Mn, Zn e particulados totais

The objective of this study was to assess a new monitoring technique of particulate and trace metals in the atmosphere via the use of a passive sampler of air pollutants in the city of Goiânia. The average particulate weight and average concentrations of metals Fe, Cr, Zn, Pb, Cu, Mn, and Cd were 0.1104 g and 257.5; 23.4; 17.8; 6.7; 1.9; 0.8; 0.2 μg/m2/day, respectively. Higher Pb and Cr concentrations were obtained in areas with intense traffic. This study revealed that it is possible to monitor trace metals with passive sampling, developed at a low cost and operational facility.

Endophytic bacteria with potential for bioremediation of petroleum hydrocarbons and derivatives

Endophytic microorganisms live inside plants and show no apparent damage for the host. They often assist in plants’ survival and facilitate their growth, or they can metabolize organic contaminants. This study aimed to isolate and identify the endophytic bacteria of plants present in impacted areas, as well as to test their ability in petroleum and their derivatives’ degradation. Plant samples were collected in an asphalt mud impacted area, and then they were superficially disinfected. After maceration and fragmentation, they were incubated at 30°C for about 72 h, when growth of microorganisms was observed in culture media. The verification of petroleum and derivatives degradation capacity was performed in ELISA plates, thereby exposing the bacteria to a solution of minimal medium, the dye DCPIP solution (2,6-dicloroindofenol sodium salt) and the petroleum or derivative tested (burning oil, lubricating oil, diesel oil and gasoline). A positive reading for degradation was observed by discoloration of DCPIP. Among nine bacteria tested, three showed degradative activity in different fractions of petroleum, diesel oil and gasoline, and others showed different profiles. Some isolates were identified from the sequencing of 16S DNA, after which they were diagnosed as Bacillus cereus, Staphylococcus pasteuri and Pseudomonas sp. The endophytic bacteria isolated from Cerrado plants confirmed their potential for application in bioremediation processes. Key words : Endophytic microorganisms, petroleum, bioremediation, Cerrado.

Earwax as an alternative specimen for forensic analysis

In this work, we presented, for the first time, earwax as an alternative forensic specimen for detecting 12 neuropsychotic drugs employing liquid chromatography–tandem mass spectrometry in positive and negative ion modes after straightforward extraction with methanol. The method was validated and standard curves were established by external calibration with correlation coefficients >0.99. All precision, accuracy, matrix effects, extraction recoveries, and carryover were within acceptable limits; limits of quantification were sufficiently low to quantify almost all the samples tested. To confirm the feasibility of the study, earwax specimens were collected from actual patients treated with different combinations of the 12 drugs and analyzed by our method; the 12 drugs could be quantified from the earwax specimens of the users successfully, showing usefulness of earwax specimens, because of its noninvasive sampling and the storage of drug(s) for relatively long time together with its being relatively less contaminated by environmental impurities. This study is pioneering; many detailed studies on earwax as an alternative specimen remain to be explored.

Characterization and quantification by gas chromatography of free steroids in unsaponifiable matter of vegetable oils

The study of free steroids and their use in oil characterization is interesting because the distribution of these steroids varies from one oil to another. Although several papers analyze the most abundant steroids in oils, studies including less common steroids are scarce. Free steroids were extracted from unsaponifiable fraction using the saponification reaction adapted micro-scale. After extraction, steroids were characterized by gas chromatography (GC) using flame ionization (FID) and mass spectrometry (MS) detectors. All chromatographic peaks in the oils that could belong to free steroids were characterized and quantified. Results evidenced great diversity in types and levels of free steroids. Corn and moringa oils had higher levels of steroids than the other oils analyzed. Babassu, palm kernel and canola oils had the lowest steroid levels.

Utilização de pelos de animais silvestres para monitoramento ambiental de Cd, Cr, Cu, Fe, Mn, Pb e Zn

This study investigates the use of wild animal hair of C. brachyurus, C. thous and L. pardalis as biomonitors of trace metal at Parque Nacional das Emas, Brazil. Results reveal a strong correlation between Cd and Pb as well as Cu and Zn, which suggests a single source of emission. Most metals showed a lower or equal concentration than those obtained in previous studies. The research shows that monitoring may be performed only with Zn, Pb, Cd, and Cr because of statistical similarity and of a non-natural occurrence of large amounts of the material under analysis.