97 resultados para physical-chemical evaluation
Resumo:
Ecological risk assessment is a process evaluating the likelihood that adverse ecological effects may occur or are occurring as a result of exposure to one or more substances. Relevant information needed to predict risks from pesticides includes their physical chemical properties, mobility in soil, persistence in the environment, and bioaccumulation and toxicity in relevant organisms. Although currently a requirement for pesticide registration in Brazil, this process is not yet fully implemented in the country. This review aims to outline the principles of environmental risk assessment for pesticides, focusing on aquatic organisms, and to discuss the studies and efforts conducted in Brazil in this area.
Resumo:
Drug trafficking and the introduction of new drugs onto the illicit market are one of the main challenges of the forensic community. In this study, the chemical profile of a new designer drug, 2-(4-iodine-2,5-dimethoxyphenyl)-n-[(2-methoxyphenyl)methyl]etamine or 25I-NBOMe was explored using thin layer chromatography (TLC), ultraviolet-visible spectrophotometry (UV-Vis), attenuated total reflection with Fourier transform infrared spectroscopy(ATR-FTIR), gas chromatography mass spectrometry (GC-MS) and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR MS). First, the TLC technique was effective for identifying spots related to 25C-, 25B- and 25I-NBOMe compounds, all with the same retention factor, Rf ≈ 0.50. No spot was detected for 2,5-dimethoxy-4-bromoamphetamine, 2,5-Dimethoxy-4-chloroamphetamine or lysergic acid diethylamide compounds. ATR-FTIR preserved the physical-chemical properties of the material, whereas GC-MS and ESI-MS showed better analytical selectivity. ESI(+)FT-ICR MS was used to identify the exact mass (m/z428.1706 for the [M + H]+ ion), molecular formula (M = C18H22INO3), degree of unsaturation (DBE = 8) and the chemical structure (from collision induced dissociation, CID, experiments) of the 25I-NBOMe compound. Furthermore, the ATR-FTIR and CID results suggested the presence of isomers, where a second structure is proposed as an isomer of the 25I-NBOMe molecule.
Resumo:
The phenanthridinone heterocyclic system has attracted considerable attention in recent years due to the diverse array of physical, chemical and pharmacological properties demonstrated by natural and synthetic derivatives. As a consequence there has been considerable development of synthetic methodology for the synthesis of this and related heterocyclic ring systems. The synthetic literature is discussed and is compared with a direct arylation methodology for the intramolecular cyclization of tertiary (2-iodo)benzoylamides to generate the biaryl bond of these compounds. The efficient methodology allowed the synthesis of a number of previously unknown phenanthridinone products. The photoluminescent properties of representative examples were characterized and it is proposed that the previously unknown compound 1s reveals dual fluorescence in a manner similar to the known compound 1r.
Resumo:
Unprocessed native starches are structurally too weak and functionally too restricted for application in today's advanced food technologies. Processing is necessary to engender a range of functionality. Naturals or natives starches can be modified by using several methods physical, chemical, enzymatic or combined, according industrial purposes. In this work, native corn starch was hydrolyzed by hydrochloric acid solution and investigated by using thermoanalytical techniques (thermogravimetry - TG, differential thermal analysis - DTA and differential scanning calorimetry - DSC), as well as optical microscopy and X-ray diffractometry. After acid treatment at 30 and 50°C, a decrease of gelatinization enthalpy (ΔHgel) was verified. Optical microscopy and X-ray diffractometry allowed us to verify the granules contorn and rugosity typical of cereal starches.
Resumo:
The use of organic matter that improves the physical, chemical and biological soil properties has been studied as an inducer of suppressiveness to soilborne plant pathogens. The objective of this work was to evaluate the effect of different sources and concentrations of organic matter on tomato bacterial wilt control. Two commercially available organic composts and freshly cut aerial parts of pigeon pea (Cajanus cajan) and crotalaria (Crotalaria juncea) were incorporated, in concentrations of 10, 20 and 30 % (v/v), into soil infested with Ralstonia solanacearum. The soil with the fresh organic matter of pigeon pea and crotalaria was incubated for 30 and 60 days before planting. Tomato seedlings of cv. Santa Clara were transplanted into polyethylene bags with 3 kg of the planting substrate (infested soil + organic matter). The wilting symptoms and percentage of flowering plants were evaluated for 45 days. All evaluated concentrations with incorporation and incubation for 30 days of aerial parts of pigeon pea and crotalaria controlled 100% tomato bacterial wilt. With 60 days of incubation, only the 10 % concentration of pigeon pea and crotalaria did not control the disease. These results suggest that soil incorporation of fresh aerial parts of pigeon pea and crotalaria is an effective method for bacterial wilt control.
Resumo:
The objective of this study was to test the hypothesis that the distribution of tree species in a fragment of submontane seasonal semideciduous forest, a buffer zone in the Parque Estadual do Rio Doce, Minas Gerais, is influenced by geomorphological and weather and soil variables, therefore it can represent a source of information for the restoration of degraded areas where environmental conditions are similar to those of the study area. A detailed soil survey was conducted in the area by sampling three soil profiles per slope segment, totaling 12 profiles. To sample the topsoil, four composite samples were collected from the 10-20 cm layers in each topographic range totaling 16 composite samples. In the low ramp and the lower and upper concave slopes, the texture ranged from clay to sandy-clay. The soil and topographic gradient was characterized by changes in the soil physical-chemical properties. The soil in the 10-20 cm sampled layer was sandier, slightly more fertile and less acid in the low ramp than the clayer soil, nutrient-poor and highly acid soil at the top. The soil conditions in the lower and upper slope of the sampled layers, in turn, were intermediate. The P levels were limiting in all soils. The species distribution along the topographic gradient was associated with variations in chemical fertility, acidity and soil texture. The distribution of Pera leandri, Astronium fraxinifolium, Pouteria torta, Machaerium brasiliense and Myrcia rufipes was correlated with high aluminum levels and to low soil fertility and these species may be indicated for restoration of degraded areas on hillsides and hilltops in regions where environmental conditions are similar. The distribution of Pouteria venosa, Apuleia leiocarpa and Acacia polyphylla was correlated with the less acid and more fertile soil in the environment of the low ramps, indicating the potential for the restoration of similar areas.
Resumo:
The aim of this study was to identify, by multivariate statistical technique, the physic, chemical and biological variables that best characterize the quality of surface waters in two small rural catchments with different land uses (eucalyptus silviculture (SC) vs. pasture and extensive livestock (LC)) located in Rosário do Sul, RS - Brazil. Monitoring was conducted during the months of August 2011 to August 2012 and the following parameters were analyzed: Ca2+, Mg2+, K+, SO42-, Cl-, pH, electrical conductivity, turbidity, alkalinity, suspended and dissolved solids, biochemical oxygen demand , total coliforms, Escherichia coli and temperature, flow and rainfall. Through the use of FA/PCA, it was found that the model best fit to express water quality of in LC that was composed of five factors which account for 83.5% of the total variance, while for SC, four factors accounted for 85.12% of the variance. In LC, the five main factors were, respectively, soluble salts, diffuse pollution, solid, and both anthropogenic and organic factors. In SC, the four factors were namely: soluble salts, mineral, nutritional and diffuse pollution factors. The results of this study showed that by replacing the traditional soil usage (pasture and livestock) with planted forest, diffuse pollution was attenuated but, however, it did not result in major changes in the physical-chemical and biological characteristics of the water. Another point to note is that factorial analysis did not result in a large reduction in the number of variables, once the best model fit occurred with the addition of 15 of 18 analyzed variables (LC) and 17 of 18 analyzed variables (SC).
Resumo:
This study aimed to investigate the potential use of magnetic susceptibility (MS) as pedotransfer function to predict soil attributes under two sugarcane harvesting management systems. For each area of 1 ha (one with green sugarcane mechanized harvesting and other one with burnt sugarcane manual harvesting), 126 soil samples were collected and subjected to laboratory analysis to determine soil physical, chemical and mineralogical attributes and for measuring of MS. Data were submitted to descriptive statistics by calculating the mean and coefficient of variation. In order to compare the means in the different harvesting management systems it was carried out the Tukey test at a significance level of 5%. In order to investigate the correlation of the MS with other soil properties it was made the correlation test and aiming to assess how the MS contributes to the prediction of soil complex attributes it was made the multiple linear regressions. The results demonstrate that MS showed, in both sugarcane harvesting management systems, statistical correlation with chemical, physical and mineralogical soil attributes and it also showed potential to be used as pedotransfer function to predict attributes of the studied oxisol.
Resumo:
In this article it was evaluated the quality of water in the Cascavel river, in the city of Cascavel - Paraná using microbiological indicators, physical and chemical pollution and susceptibility / resistance in strains of Escherichia coli isolated antimicrobial trade. The water sampling was conducted between 2010-July and 2011-June at three points: a) near the source, b) urban area, c) rural area. The samples were analyzed for physical, chemical and microbiological variables: temperature, pH, color, turbidity, electrical conductivity, total nitrogen and total phosphorus, total coliforms (CT), fecal coliform (CTe) and Escherichia coli. Tests were also performed to nine antimicrobial commercial resistances. The variables studied indicated that the Cascavel river water was presented at disagreement with the resolution 357/2005 CONAMA (class I), ranking in the index as regular water quality. The physical, chemical and rainfall did not affect the growth of CT and CTe, with higher counts of E. coli in the urban area. The greatest resistance profiles of the strains of E. coli isolated from Cascavel river water was found in section 2, the urban area as a probable consequence of human influence on water quality.
Resumo:
Cashew (Anacardium occidentale L.) apples from Pacajus, Ceará State, Brazil, were processed into high pulp content juice. The juice was packed either by hot fill or an aseptic process and evaluated for physical, physical-chemical, and sensorial changes during a 12-month storage period at room temperature. The results indicated that pH, soluble solids, total acidity, total sugar content and color did not change significantly during storage nor were affected by the type of filling. The sensorial analysis showed that juice acceptance remained high throughout the storage period regardless of the filling system. Differences in juice viscosity persisted between both processes.
Resumo:
Aiming at improving the quality of Perna perna mussels cultivated and commercialized in Ubatuba, SP, Brazil, the growth and elimination of Staphylococcus aureus and Bacillus cereus artificially inoculated in mussels were studied. The inoculation was carried out in "in natura" and pre-cooked mussels for 30 min, and after that the mussels were kept for 10 hours at room temperature (25 ± 1 °C) and under refrigeration (7 ± 1 °C). Six thermal treatments were evaluated: three using steam (5, 10 and 15 minutes) and three in boiling water (5, 10 and 15 minutes), in order to find the best time/temperature binomial to provide pathogenic control. Yield and physical-chemical and sensory characteristics were evaluated. All thermal treatments were efficient to eliminate microorganisms in 2 logarithmic cycles. However, the boiling water treatments presented better results than the steam treatments. The physical-chemical and sensory analyses did not show statistical differences among the thermal treatments studied. The best performances were reached in the shortest times of heat exposure. Overall, the treatments in boiling water presented better results than the steam treatments.
Resumo:
Pleurotus ostreatus, worldwide known as oyster mushroom, was cultivated in banana straw using inocula produced by two different processes - liquid inoculum and the traditionally used solid inoculum. Different ratios (5, 10, 15, and 20%) were tested. Biological efficiency, yield, productivity, organic matter loss, and moisture of fruiting bodies as well as physical-chemical characteristics of banana straw were studied. Significant differences were observed for cellulose, lignin, and hemicellulose content between one and two harvests for both solid and liquid inocula. It was observed that P. ostreatus growth promoted higher degradation of lignin (80.36%), followed by hemicellulose (78.64%) and cellulose (60.37%). Significant differences between one and two harvests were also observed for the production parameters (biological efficiency and yield) for both kinds of inocula, liquid and solid. However, significant differences in productivity between harvests were observed only for solid inoculum.
Resumo:
The Graphite furnace atomic absorption spectrometry (GF AAS) was the technique chosen by the inorganic contamination laboratory (INCQ/ FIOCRUZ) to be validated and applied in routine analysis for arsenic detection and quantification. The selectivity, linearity, sensibility, detection, and quantification limits besides accuracy and precision parameters were studied and optimized under Stabilized Temperature Platform Furnace (STPF) conditions. The limit of detection obtained was 0.13 µg.L-1 and the limit of quantification was 1.04 µg.L-1, with an average precision, for total arsenic, less than 15% and an accuracy of 96%. To quantify the chemical species As(III) and As(V), an ion-exchange resin (Dowex 1X8, Cl- form) was used and the physical-chemical parameters were optimized resulting in a recuperation of 98% of As(III) and of 90% of As(V). The method was applied to groundwater, mineral water, and hemodialysis purified water samples. All results obtained were lower than the maximum limit values established by the legal Brazilian regulations, in effect, 50, 10, and 5 µg.L-1 para As total, As(III) e As(V), respectively. All results were statistically evaluated.
Resumo:
The objective of this study was to add value to araça and marolo fruits by developing jams and verifying changes in their physical, chemical, and microbiological parameters during storage. The analyses were carried out every 2 months. From the results, it was shown that the levels of moisture (35.89 - 26.34%), lipids (0.43 - 0.27%), sucrose (30.62 - 28.98%), total pectin (0.83 - 0.50%), soluble pectin (0.52 - 0.38%), total phenolic compounds (180.31 - 135.52 mg.GAE 100 g-1), and organic acids (401.1 - 68.5 µg.g-1 citric acid) decreased during storage. However, the levels of protein (0.83 - 0.95%), carbohydrate (62.52 - 72.5%, calories (257,11 - 295,931 kcal), fiber (0.72 - 1.4%), total soluble sugar (62.52 - 70.44%), reducing sugar (32.05 - 41.41%), soluble solids (68.4 - 72.18 °Brix), consistency (0.33 - 0.44 N), total antioxidant potential (11.3 - 22.63%), and color (a* 7.56 - 9.49, and b* 8.63 - 10.49) increased during 1-year storage. The quality of the fruit jams studied was in accordance with the microbiological standards established by the Brazilian legislation. It was concluded that the mixed araça and marolo jam can be stored for 1 year without the addition of additives.
Resumo:
The effect of replacing shortening and sugar on the physical and chemical properties of mangaba ice cream and its acceptability were evaluated. Ice cream formulations were tested with the following fat replacers: Selecta Light, Litesse, and Dairy Lo and the following sugar substitutes: Lactitol and Splenda. All formulations were subjected to physical, chemical, and microbiological analyses and evaluated by acceptability tests. In the sensory analysis, it was observed a larger acceptance of the formulations containing Selecta Light (SL) and the combination of Litesse, Lactiol, and Splenda (LLS). The largest reduction in total energetic value (50%) was observed in the formulation LLS. The use of fat and/or sugar substitutes caused a reduction in the air incorporation (overrun) and affected viscosity. The highest melting speed was observed in the formulation with Dairy-Lo, Lactitol, and Splenda. All formulations showed good levels of global acceptability and appearance. The substitution of shortening for fat replacers caused a reduction in air incorporation and changes in ice-cream viscosity. The low-fat mangaba ice-cream elaborated with Selecta Light was the best formulation in terms of viscosity and air incorporation when compared with the control. It also showed a good level of acceptability and low fat content.