Análise de resíduos de agrotóxicos em tomates empregando dispersão da matriz em fase sólida (DMFS) e cromatografia gasosa

This work was aimed on optimization of the matrix solid-phase dispersion (MSPD) technique using gas chromatography for analyzing residues of chlorpyriphos, λ-cyhalothrin, cypermethrin and deltamethrin in tomatoes. The results showed that silica was more efficient for the clean up of extracts, but florisil provided the highest recovery rates. A 2³ complete factorial design was carried out to evaluate the absorbent/sample ratio, presence of co-column (silica) and ultrasonic bath on the extraction rate. The percentage of extraction of the pesticides chlorpyriphos, λ-cyhalothrin, cypermethrin and deltamethrin were 64.7, 88.3, 99.2 and 89.2%, respectively, with relative standard deviations below 5%.

Produção de biossurfactante por Aspergillus fumigatus utilizando resíduos agroindustriais como substrato

The objective of this study was to investigate biosurfactant production in solid state by Aspergillus fumigatus in fixed-bed column bioreactors using substrate based on agricultural residues. Without a supplementary carbon source the highest emulsifying activity (EA) was 11.17 emulsifying units (EU) g-1 of substrate at an aeration rate of 148 mL h-1g-1 but in the presence of diesel oil the highest EA value was 9.99 EU g-1 at an aeration rate of 119 mL h-1g-1 of substrate while supplementation with soya oil resulted in only 8.47 EU g-1 of substrate at an aeration rate of 119 mL h-1g-1.

Aproveitamento sustentável de biomassa e de recursos naturais na inovação química

Increased production of biomass is currently the only immediately accessible alternative for large-scale carbon sequestration and it can produce large amounts of food, fuel and raw materials for the chemical industry that can in turn growingly replace oil as a source of organic building blocks and also of hydrogen and sulfur. Development of processes for biomass and abundant minerals transformation into chemical raw materials should now benefit from large inputs from nanotechnologies, biotechnologies, information and micro-reactor technologies. Success in R&D&Innovation along this line can yield new products and processes needed to perform desirable functions within a sustainable development paradigm.

Avaliação da contaminação do Igarapé do Sabino (Bacia do Rio Tibiri) por metais pesados, originados dos resíduos e efluentes do Aterro da Ribeira, em São Luís, Maranhão

This work aimed to carry out an environmental monitoring in sabino narrow river (affluent of Tibiri Basin, in São Luís - MA, Brazil), in order to verify the main environmental impacts caused by effluent residues from Ribeira landfill. Chemical analysis and bibliographic and cartographic researches on this ecosystem were also carried out. In addition, heavy metals, such as Hg, Pb and Zn, were investigated in water samples by ICP-MS technique. It was observed that the contents of such heavy metals were above the tolerance limits established by the Brazilian legislation, showing a strong impact level on the evaluated ecosystem.

Resíduos de agrotóxicos em alimentos: uma preocupação ambiental global - Um enfoque às maçãs

This paper describes the use of pesticides in agriculture. Research has shown that significant quantities of pesticide residues have been found in many types of foods. Thus, an overview is given of pesticide residue determinations in fruits and vegetables, with special attention to apples. The toxicity and the adverse effects possibly caused by the exposure of these compounds are alerting the scientific community to develop studies about the validation of analytical methods for multiresidue pesticide determination in these samples. This review shows that pesticide-residue determination in apples is becoming a very important and challenging issue.

Distribuição e biodisponibilidade de crômio em solos contaminados por resíduos de couro

Samples of soil, water and sediment were collected and analyzed in order to evaluate chromium contamination due to deposition of tannery residues onto soils under different management regimes. The results showed that soils used for sugar cane cultivation were not adversely impacted. However, in the case of mango plantations, variable concentrations of chromium were measured in the soil profile, with 22.2% of values being higher than permitted legal limits, and 38.9% being at levels requiring remediation. Concentrations of bioavailable chromium were lower than the detection limit of the method (0.01 mg of chromium kg-1 of soil), indicating that all of the chromium present in the samples was either complexed or in an insoluble form. Chromium concentrations measured in samples of water and sediments were indicative of low mobility of the metal in soils. The main cause of differences found between soil samples obtained from different cultivations was the type of soil management.

Determinação de resíduos de pesticidas em plasma bovino por cromatografia gasosa-espectrometria de massas

An analytical method for the isolation based on matrix solid-phase dispersion technique and gas chromatographic determination of pesticides in cattle plasma is presented. It was fortified 0.25 g of plasma with pesticides and blended with 1 g each C18 and Na2SO4. The homogenized matter was transferred to a SPE cartridge, which contained 1 g of activated florisil with 5 mL acetonitrile. The analites were eluted under vaccum with 15 mL acetonitrile, the extract was analyzed by gas chromatography-mass spectrometry. The limit of quantification of the method was 0.04 mg L-1 for chlorphenvinfos and fipronil and 0.02 mg L-1 for cypermethrin..

Determinação simultânea de resíduos de sulfametoxazol e trimetoprima em superfícies de equipamentos de produção

A cleaning validation method was developed and validated, based on swabbing sampling and simultaneous chromatographic determination of sulfamethoxazole (SMX) and trimethoprim (TMP) residues. The method presented limits of detection of 0.06 mg mL-1 for SMX and 0.09 mg mL-1 for TMP. It was considered selective, precise, accurate and robust according to the guidelines from ANVISA, the Brazilian regulatory agency, and International Conference on Harmonization. Mean swab recovery factors of 98.5% for SMX and 97.7% for TMP were obtained for spiked stainless steel plates. The method was successfully applied to the assay of actual swab samples collected from eleven points on an equipment surface.

Alternativa potencial para aproveitamento do glicerol gerado na produção de biodiesel: síntese enzimática de monolaurina por esterificação

Esterification reactions of glycerol with lauric acid in solvent free system were carried out using lipases from several sources. All lipases were immobilized on polysiloxane-polyvinyl alcohol particles by covalent binding with high activity recovered. Among the tested enzymes, the Candida antarctica lipase allowed to attain the highest molar conversion (76%), giving similar proportions of monolaurin, dilaurin and low amount of trilaurin. To further improve the process, the Response Surface Methodology (RSM) was used and optima temperature and molar ratio glycerol to lauric acid were found to be 45 ºC and 5:1, respectively. Under these conditions, 31.35% of monolaurin concentrations were attained and this result was in close agreement with the statistical model prediction.

Otimização e validação intralaboratorial de método para análise de resíduos de cloranfenicol em leite caprino por cromatografia gasosa com detecção por captura de elétrons (CG/DCE)

The presence of chloramphenicol residues in goat milk can cause toxic effects in the population. The present work consists of the optimization and validation of analytical methodology for determination of chloramphenicol residues in goat milk by GC/ECD. The extraction was made with ethyl acetate and the clean-up with SPE-C18. The identification was made by comparison of retention time and GC/MS, and the quantification by external standard. The method was selective, linearity (0.998), precise (5.8-13.4%), exact (69.87-73.71%) and robust. The LOD and LOQ of method were 0.030 and 0.10 μg/kg, respectively. The method was efficiently for analysis of chloramphenicol in goat milk.

Produção, propriedades e aplicação de celulases na hidrólise de resíduos agroindustriais

Cellulases have been intensively studied in the past few years, due to the interests in biofuels production from lignocellulosic materials, since they permit maintaining mild conditions during the conversion process. These enzymes can be produced by a broad variety of naturally occurring microorganisms, such as from genera Aspergillus, Trichoderma, Penicillium and Humicola. Targeting the increasing of expression levels, molecular biology tools have been used for heterologous genes insertion in host cells, e. g., Pichia pastoris and Escherichia coli. Enzymes from fungal cellulolytic complex usually act best at pH between 4 and 5 under temperatures from 40 to 60 °C and can be used for either sequential (SHF) or simultaneous (SSF) hydrolysis together alcoholic fermentation. In this review, the main raw materials for production of cellulases are identified, as well as the state of art of enzymes' properties, production and main applications.

Utilização de resíduos agroindustriais para a produção de proteases pelo termofílico Bacillus sp em fermentação submersa: otimização do meio de cultura usando a técnica de planejamento experimental

Thermophilic Bacillus sp. SMIA-2, produced protease when grown on apple pectic, whey protein and corn step liquor medium, whose concentration was varied from 3 to 10 gL-1, according to the central composite design 2³. The experiments were conducted in shaker, at 50 °C, 150 rpm and initial pH 6.5. The results revealed that the culture medium affected both, cell growth and enzyme production. After graphical and numerical optimization procedure, the enzyme production reached its maximum value at 30 h fermentation, reaching, approximately, 70 U protein mg-1, suggesting that this process was partially associated to the growth.

Validação de método para determinação de resíduos de amoxicilina aplicado à validação de limpeza em indústria farmacêutica de penicilânicos

The aim of this work was the single-laboratory validation of a quantitative method for the determination of amoxicillin residues in support of cleaning control and validation. Linearity was demonstrated between 2.5 and 17.5 μg/mL, without matrix effects. Mean recoveries ranged from 84.00 to 103.74% and the relative standard deviation under repetitivity and within-reproducibility conditions were from 0.58 to 4.20% and from 0.79 to 4.39%, respectively. The theoretical limits of detection and quantification were 0.133 and 0.442 μg/mL, respectively. The studied method was suitable for cleaning control purpose within good manufacturing practices.

Reciclagem do crômio de resíduos químicos provenientes da determinação de carbono oxidável em fertilizantes orgânicos

This work proposes a separation, recovery and reuse procedure of chemical residues with chromium. This residue was generated by the determination of oxidizable carbon in organic fertilizers samples. The Cr(VI) of the residue was reduced with ethanol and precipitated with NaOH. The Cr(OH)3 precipitate was separated and oxidized to dichromate ions with hydrogen peroxide. This solution was used another time in organic carbon determination. The uses of recycled dichromate solution were appropriated in four successive recycling. The accuracy was proven using potassium hydrogen phthalate and ten organic fertilizer samples. The organic carbon results, determined with recycled solutions, were similar the conventional solution.