DEQUI - Departamento de Química
URI Permanente desta comunidade
Navegar
Navegando DEQUI - Departamento de Química por Autor "Afonso, Robson José de Cássia Franco"
Agora exibindo 1 - 20 de 48
Resultados por página
Opções de Ordenação
Item Analysis of tylosin in poultry litter by HPLC-UV and HPLC-MS/MS after LTPE.(2020) Paranhos, Aline Gomes de Oliveira; Pereira, Andressa Rezende; Fonseca, Isadora Chagas da; Sanson, Ananda Lima; Afonso, Robson José de Cássia Franco; Aquino, Sergio Francisco deThe growing demand for chicken meat in Brazil encourages poultry producers to invest in antibiotics as growth promoters to ensure the quality of their products. Among these, the antibiotic tylosin is a widely used growth promoter that assists in the treatment of necrotic enteritis. Antibiotics usually are not totally metabolised and may be excreted in its original form, thereby contaminating different environmental compartments and may induce microbial resistance. Therefore, analyses of such contaminants in different matrices are important to perform risk assessments and this often depends on the development of extraction methods to allow the quantification of the substance at low concentrations. This work presents a simple and cheap methodology which employs low-temperature partitioning extraction (LTPE) for the analysis of tylosin in poultry litter samples by HPLC-UV and HPLC-MS/MS. The analytical method developed was validated according to Brazilian regulating agencies (ANVISA and MAPA) and resulted in method detection (LDM) and quantification (LQM) limits of 6.32 μg.kg−1 and 21.12 μg.kg−1, respectively. The analysis of the waste from a chicken broiler company, located in Minas Gerais, confirmed the adequacy of the method, since it detected tylosin at average concentrations of 135.22 μg.kg−1 and 264.92 μg.kg−1 in poultry litter from sheds containing birds in the rearing and production phase, respectively.Item Assessment of conventional full-scale treatment for the removal of endocrine disruptors and pharmaceuticals present in the Tibagi river -Paraná state, Brazil-.(2021) Fazolo, Ajadir; Batista, Lígia Flávia Antunes; Nonaka, Fernanda Martins; Sanson, Ananda Lima; Alves, Mariana Corrêa Pessato; Afonso, Robson José de Cássia Franco; Aquino, Sergio Francisco deThe concentrations of 25 pharmaceuticals and endocrine disruptors were monitored in the water coming from the Tibagi River (State of Paraná, Brazil) and in a conventional water treatment plant over 13 sampling campaigns. In raw water, only 3 compounds (bisphenol A, dexamethasone and losartan) were detected with high frequency (>75%) and 4 drugs (estradiol, diclofenac, loratadine and naproxen) were found with moderate frequency (between 30 and 70%). In addition, 7 micropollutants (paracetamol, ethinylestradiol, caffeine, propanolol, diltiazem, benzafibrate and promethazine) were not detected in any of the samples analyzed and 11 other compounds were quantified at low frequency (up to 25%). The conventional treatment process employed at WTP- Jataizinho has proven to be very efficient in removing dexamethasone (∼99%), moderately efficient in reducing bisphenol A (∼47%) concentration and inefficient in removing losartan (∼22%) and loratadine (not removed). The greatest removals were observed during the water clarification stage using aluminum sulfate as coagulant. In general, the dry and rainy seasons did not influence the concentrations of pharmaceuticals and endocrine disruptors in raw water. In terms of the 5 most prevalent micropollutants in treated water (bisphenol A, losartan, dexamethasone, loratadine and naproxen), the human health risk associated with ingesting contaminated water was assessed and considered negligible.Item Avaliação da presença de microcontaminantes de preocupação emergente, por GC-MS, e de elementos inorgânicos, por TXRF, nas águas superficiais da Bacia do Rio Paraopeba/MG.(2018) Corrêa, Joane Mariela Miari; Afonso, Robson José de Cássia Franco; Moreira, Renata Pereira Lopes; Baeta, Bruno Eduardo Lobo; Afonso, Robson José de Cássia FrancoA significativa diminuição do volume dos recursos hídricos e a constante poluição dos corpos d’águas por contaminantes orgânicos têm despertado a atenção para a necessidade de estudos dedicados à determinação destas substâncias, presentes no meio ambiente, e às alternativas de tratamento para remoção destes poluentes e recuperação dos sistemas afetados. Várias substâncias, frequentemente encontradas em baixas concentrações, são classificadas como microcontaminantes de preocupação emergente, devido às alterações que provocam no meio ambiente causando efeitos adversos para os seres vivos pela exposição contínua. Abrangem diversas classes de substâncias, tais como produtos farmacêuticos e de higiene pessoal, pesticicidas, herbicidas, nanomateriais, hormônios naturais e sintéticos. Os elementos inorgânicos também estão presentes em níveis elevados nas matrizes ambientais, representando potenciais riscos aos corpos hídricos, biota e saúde humana. Dessa forma, o presente trabalho buscou identificar e quantificar alguns microcontaminantes de preocupação emergente utilizando cromatografia gasosa acopladas à espectrometria de massas (GC-MS) e elementos inorgânicos por fluorescência de raios-X por reflexão total (TXRF) nas águas superficiais da Bacia do Rio Paraopeba-MG. As coletas das amostras foram realizadas em 4 campanhas, sendo 2 em período de chuva e 2 de estiagem. Foram selecionados 15 pontos de amostragem ao longo da bacia, assim, foi possível avaliar as variações sazonal e espacial dos compostos e observar a influência das diferentes atividades antropogênicas. Os 12 microcontaminantes de preocupação emergente selecionados foram: diclofenaco, ibuprofeno, naproxeno, paracetamol, genfibrozila, estrona, 17β-estradiol, 17α-etinilestradiol, estriol, bisfenol A, 4-nonilfenol, 4-octilfenol. Os 15 elementos inorgânicos foram: arsênio, bário, bromo, cálcio, chumbo, cobre, cromo, estrôncio, ferro, manganês, níquel, potássio, rubídio, titânio e zinco. A metodologia utilizada para a detecção destes compostos foi validada e aplicada em 60 amostras. Os procedimentos para a determinação dos compostos orgânicos envolveram filtração a vácuo seguida pela concentração e clean-up das amostras utilizando extração em fase sólida (SPE). Os extratos analisados por cromatografia gasosa acoplada à espectrometria de massa (GC-MS) foram previamente derivatizados com BSTFA: 1% TMCS, apresentando limites de quantificação para o método de 3,61 a 14,36 ng/L e valores de recuperação variaram de 46,11 a 107,15% para o nível mais baixo (10μg/L). As análises dos elementos inorgânicos foram realizadas por fluorescência de raios-X por reflexão total (TXRF). Os limites de quantificação do método foram de 4,47 a 111,63 µg/L. O microcontaminante de preocupação emergente de maior ocorrência foi o bisfenol A, detectado em 96,67% das amostras analisadas.Já os inorgânicos de maior incidência foram o cálcio e potássio encontrados em 100% das amostras. A ocorrência do maior número de microcontaminantes de preocupação emergente foi no período de menor índice pluviométrico, campanha 4. Os elementos inorgânicos tiveram maiores concentrações nas amostras coletadas no período das águas, campanha 1 e 2. Os dados obtidos foram tratados estatisticamente por análises multivariadas (PCA e HCA), sendo possível observar o perfil de contaminação das amostras coletadas e correlacioná-los com as influências antropogênicas, industriais e/ou naturais no processo de contaminação das águas superficiais da Bacia do Rio Paraopeba em Minas Gerais. Enfim, foi calculada uma estimativa da toxicidade de alguns microcontaminantes de preocupação emergente deste estudo.Item Avaliação da remoção de fármacos e de desreguladores endócrinos em águas de abastecimento por clarificação em escala de bancada.(2014) Lima, Diego Roberto Sousa; Afonso, Robson José de Cássia Franco; Libânio, Marcelo; Aquino, Sergio Francisco deIn this work, the efficiency of clarification treatment (coagulation, flocculation and sedimentation) with polyaluminum chloride (PAC) and aluminum sulfate (SA) as coagulants was evaluated in the removal of 7 microcontaminants (diclofenac - DCF, sulfamethoxazole - SMX, ethinylestradiol - EE2, bisphenol-A - BPA, estradiol - E2, estrone - E1 and estriol - E3) in water of low and high turbidity. The clarification treatment led to poor removal rates (40% at most) for all microcontaminants except SMX which exhibited intermediate removal efficiency (67 to 70%). Overall, PAC application yielded better performance compared to SA.Item Behavior of micropollutants in polishing units that combine sorption and biodegradation mechanisms to improve the quality of activated sludge effluent.(2018) Castro, Lucas Vassalle de; Brandt, Emanuel Manfred Freire; Campos, Alexandre Cristiano Vicente; Aquino, Sergio Francisco de; Werner, David; Afonso, Robson José de Cássia Franco; Mota Filho, Cesar RossasThe current study evaluated the removal of six micropollutants (estrone (E1); 17β-estradiol (E2); 17α-ethynylestradiol (EE2); ibuprofen (IBP), diclofenac (DCF), and paracetamol (PCT)) from the final effluent of an activated sludge domestic sewage treatment plant using polishing filters. Four polishing filters were assembled as columns and filled with a mixture of sand and vermiculite, sand and charcoal, sand and granulated activated carbon (9:1 by volume), and sand only. The column filters were placed near the outlet of a full-scale activated sludge treatment plant and were fed with a treated effluent containing from 4.71 to 28.93 ng L-1 of the target compounds at a hydraulic loading rate (HLR) of 50 m3 m−2 day−1. Samples were collected periodically from the influent (biologically treated sewage) and effluent of the four columns and analyzed for estrogens, anti-inflammatories, and analgesic compounds. Liquid samples were submitted to a solid phase extraction (SPE) and analyzed by gas chromatography coupled with mass spectrometry after their derivatization. Among the compounds found, diclofenac was distinguished by the high occurrence of detection in the samples (85%) and higher mean concentration (~ 17 ng L−1). High removal efficiency (> 90%) of the estrogens was observed in the polishing systems studied, while for the other targets, the removal efficiency varied from 10 to 30%. The concentration values of some compounds were low, probably due to rainfall during the sampling period.Item Behavior of pharmaceuticals in UV photoreactors fed with sewage treated by anaerobic/aerobic system.(2017) Lopes, Bruna Coelho; Sanson, Ananda Lima; Aquino, Sergio Francisco de; Souza, Cláudio Leite de; Chernicharo, Carlos Augusto de Lemos; Afonso, Robson José de Cássia FrancoThis work has assessed the seasonal changes and the dynamics in the concentration of six pharmaceutical compounds during photolysis as a tertiary treatment of sewage previously treated by an anaerobic/aerobic system comprised by a UASB (Upflow Anaerobic Sludge Blanket) reactor and a trickling filter (TF). The target compounds were 4 antibiotics (ciprofloxacin, clindamycin, sulfamethoxazole, trimetoprime), 1 beta blocker (atenolol) and 1 anti-inflammatory (diclofenac). Six hydraulic retention times (HRT) were evaluated (5, 10, 20, 40, 80 and 160 minutes) with the intent of varying the UVC radiation doses applied to the effluent from biological treatment containing the target contaminants. The concentrations of pharmaceutical compounds in the effluent of the UASB/TF system were in agreement with the concentration levels reported in the literature. Aside from DCF, the seasonality seems to be a preponderant characteristic regarding the pharmaceutical concentration found in the effluent of biological treatment systems. The radiation dose of 117 mJ.cm-² seemed to be most suited for the photolysis application to tertiary treatment of domestic effluents. It was observed that lower UVC doses led to deconjugation of pharmaceuticals which can result in increased concentrations of target pollutants in the photo-reactor effluent.Item Behaviour of pharmaceuticals and endocrine disrupting chemicals in simplified sewage treatment systems.(2013) Brandt, Emanuel Manfred Freire; Queiroz, Fernanda Barbosa de; Afonso, Robson José de Cássia Franco; Aquino, Sergio Francisco de; Chernicharo, Carlos Augusto de LemosThis work assessed the behaviour of nine pharmaceuticals and/or endocrine disrupting chemicals (EDCs) in demo-scale upflow anaerobic sludge blanket reactors (UASB reactors) coupled to distinct simplified post-treatment units (submerged bed, polishing ponds, and trickling filters) fed on raw sewage taken from a municipality in Brazil. The dissolved concentration of the studied micropollutants in the raw and treated sewage was obtained using solid phase extraction (SPE) followed by analysis in a liquid chromatography system coupled to a hybrid high resolution mass spectrometer consisting of an ion-trap and time of flight (LC-MS-IT-TOF). The UASB reactors demonstrated that they were not appropriate for efficiently removing the assessed compounds from the sewage. Furthermore, this study demonstrated that the hydraulic retention time (HRT) was an important parameter for the removal of the hydrophilic and less biodegradable compounds, such as trimethoprim and sulfamethoxazole. The post-treatment units substantially increased the removal of most target micropollutants present in the anaerobic effluents, with a greater removal of micropollutants in simplified systems that require a large construction area, such as the submerged bed and polishing ponds, probably because of the higher HRT employed. Alternatively, compact post-treatment systems, such as trickling filters, tended to be less effective at removing most of the micropollutants studied, and the type of packing proved to be crucial for determining the fate of such compounds using trickling filters.Item Biotechnological potential of yeast isolates from cachaça : the Brazilian spirit.(2015) Conceição, Luís Eduardo Fernandes Rodrigues da; Saraiva, Margarete Alice Fontes; Diniz, Raphael Hermano Santos; Oliveira, Juliana; Barbosa, Gustavo Dimas; Alvarez, Florencia; Correa, Lygia Fátima da Mata; Mezadri, Hygor; Coutrim, Maurício Xavier; Afonso, Robson José de Cássia Franco; Lucas, Cândida Manuel Ribeiro Simões; Castro, Ieso de Miranda; Brandão, Rogélio LopesThis study identified phenotypic traits appropriate for biotechnological applications of 118 yeasts isolated from cachaça distilleries. Different properties were verified: capacity to use alternative carbon sources; ability to tolerate high concentrations of sucrose, ethanol, methanol, aluminum and zinc as well as different pH values and foam production. Pichia guilliermondii and Pichia anomala strains were identified as the most promising ones for application in the second-generation biofuel industry, showing ability to grow on high glycerol concentrations. Other isolates, identified as Saccharomyces cerevisiae, produced bioethanol comparable to the industrial strains, and were therefore ideal for use in the first-generation ethanol industry. Some of these strains also showed high resistance to aluminum, as observed in sugarcane juice, and to intercycle washings with diluted sulphuric acid, as performed in the industrial bioethanol production process. In summary, yeast isolates from cachaça distilleries displayed robustness and phenotypic plasticity, which makes them interesting for biotechnological applications.Item Can high rate algal ponds be used as post-treatment of UASB reactors to remove micropollutants?(2020) Castro, Lucas Vassalle de; García Galán, María Jesús; Aquino, Sergio Francisco de; Afonso, Robson José de Cássia Franco; Ferrer, Ivet; Passos, Fabiana; Mota Filho, Cesar RossasThe present study evaluated the removal capacity of a UASB-HRAP treatment system, combining anaerobic and microalgae-based, aerobic treatment, for eleven organic micropollutants present in raw sewage, including pharmaceuticals, estrogens and xenoestrogens. The UASB reactor and the HRAP were operated at a hydraulic retention time (HRT) of 7 h and 8 days, respectively. Influent and effluent samples from the UASB and HRAP were collected periodically. All the target compounds were detected in raw sewage, with an occurrence ranging from 70 to 100%. Removal rates in the UASB reactor were generally incomplete, ranging from no removal (25.12% for the hormone EE2-ethinylestradiol) to 84.91% (E2 - estradiol). However, the overall performance of the UASB þ HRAP system was highly efficient for the majority of the compounds, with removal rates ranging from 64.8% (ibuprofen) to 95% (estrone). Gemfibrozil and bisphenol A were the only exceptions, with overall removal rates of 39% and 43%, respectively. Hormones were the compounds with the highest removal rates in the system.Item Caracterização de contaminantes presentes em sistemas de tratamento de esgotos, por cromatografia líquida acoplada à espectrometria de massas tandem em alta resolução.(2010) Leite, Gustavo de Sousa; Afonso, Robson José de Cássia Franco; Aquino, Sergio Francisco deThis work shows results on the characterization, by liquid chromatography coupled to high resolution tandem mass spectrometry (LC-IT-TOF-MS) with electrospray ionization, of organic compounds present in raw and treated effluents from a combined sewage treatment systems (upflow anaerobic sludge blanket-trickling filter). The sewage samples were prepared by C18 solid phase extraction and the spectra obtained from the various extracts were submitted to principal component analysis to evaluate their pattern and identify the major deprotonated species. Some target compounds were submitted to semiquantitative analysis, using phenolphtalein as internal standard. The results showed the anaerobic step had little impact on the removal of anionic surfactants (LAS), fatty acids, and some contaminantes such as bisphenol A and bezafibrate, whereas the aerobic post-treatment was very efficient in removing these organics.Item Characterization of enalapril and ranitidine chlorination by-products by liquid chromatography/high-resolution mass spectrometry and their toxicity evaluation.(2017) Quintão, Frederico Jehár Oliveira; Souza, Mariana Pierotti de; Silva, Silvana de Queiroz; Aquino, Sergio Francisco de; Afonso, Robson José de Cássia FrancoDue to its low cost, its capability for disinfection and oxidation, chlorination using gaseous chlorine or hypochlorite salts, has also been commonly applied in water treatment plants for oxidation and disinfection purposes. Little is known about the identity and toxicity of by-products resulting from the chlorination of pharmaceutical micropollutants, such as enalapril (ENA) and ranitidine (RAN). ENA and RAN chlorination by-products were characterized in this study by high-performance liquid chromatography coupled to high-resolution mass spectrometry (HPLC/HRMS) and their toxicity were assessed by MTT assay. Chlorination experiments with ENA and RAN solutions (10 mg L-1) indicate degradation efficiencies of 100% for both compounds after only 5 min of exposure to chlorine at concentration of 9.53 mg Cl2 L-1. On the other hand mineralization rates were lower than 3%, thereby indicating there was accumulation of degradation by-products in all experiments. Mass spectrometric analysis revealed, at all times of reaction after the addition of hypochlorite, the presence of 1-(2-((4-(chlorophenyl)-1-ethoxy-1-oxobutan-2-yl)amino)propanoyl)pyrrolidine-2-carboxylic acid (enalapril by-product) and N-chloro-N-(2-(((chloro-5-((dimethylamino)methyl)furan-2-yl)methyl)sulfinyl)ethyl)-N-methyl-2- nitroethene 1,1-diamine (ranitidine by-product). Despite the formation of oxidized chlorinated by-products in all chlorination assays, the treated solutions were nontoxic to HepG2 cells by the MTT assay. It has been observed that chlorination (10 mg L-1, 5 min) of ENA and RAN solutions exhibited high degradation efficiencies of the target compounds and low mineralization rates. Based on the mass spectrometry data, the routes for ENA and RAN successive oxidation by chlorine has been proposed.Item Chemical fingerprint of non‐aged artisanal sugarcane spirits using kohonen artifcial neural network.(2022) Caetano, Daniela; Lima, Clara Mariana Gonçalves; Sanson, Ananda Lima; Silva, Débora Faria; Hassemer, Guilherme de Souza; Verruck, Silvani; Gregório, Sandra Regina; Silva, Gilmare Antônia da; Afonso, Robson José de Cássia Franco; Coutrim, Maurício Xavier; Batiha, Gaber El‐Saber; Gandara, Jesus SimalThis study focuses on the determination of the chemical profle of 24 non-aged Brazilian artisanal sugarcane spirits (cachaça) samples through chromatographic quantifcation and chemometric treatment via principal component analysis (PCA) and Kohonen’s neural network. In total, forty-seven (47) chemical compounds were identifed in the samples of non-aged artisanal cachaça, in addition to determining alcohol content, volatile acidity, and copper. For the PCA of the chemical compounds’ profle, it could be observed that the samples were grouped into seven groups. On the other hand, the variables’ bearings were grouped together, making it difcult to separate the components in relation to the sample groups and reducing the chances of obtaining all the necessary information. However, by using a Kohonen’s neural network, samples were grouped into eight groups. This tool proved to be more accurate in the groups’ formation. Among the chemical classes of the com- pounds observed, esters stood out, followed by alcohols, acids, aldehydes, ketones, phenol, and copper. The abundance of esters in these samples may suggest that these compounds would be part of the regional standard for cachaças produced in the region of Salinas, Minas Gerais.Item Chemometric approach to optimize the operational parameters of ESI for the determination of contaminants of emerging concern in aqueous matrices by LC-IT-TOF-HRMS.(2014) Rodrigues, Keila Letícia Teixeira; Sanson, Ananda Lima; Quaresma, Amanda de Vasconcelos; Gomes, Rafaela de Paiva; Silva, Gilmare Antônia da; Afonso, Robson José de Cássia FrancoContaminants of emerging concern are organic compounds used in large quantities by the society for various purposes. They have shown biological activity at lowconcentrations,which gives great environmental relevance. The difficulty to detect and quantify contaminants of emerging concern in the environment stimulates the development of appropriate analytical methods. In this work a chemometric approach to positive and negative electrospray ionization (ESI) optimization for the simultaneous determination of contaminants of emerging concern in water samples by liquid chromatography-ion trap-time of flight-high resolution mass spectrometry (LC-IT-TOF-HRMS) was applied. Three types of phase modifiers were used: formic acid, ammonium hydroxide and formic acid/ammonium formate. The effects of operational parameters such as mobile phase modifier concentrations, mobile phase flow rate, heating block temperature and drying gas flow rate were evaluated by the 24− 1 fractional factorial experimental design, resolution IV, in the screening phase and byDoehlert experimental design. Initial factorial experimental design studies indicated that the phasemodifier ammonium hydroxide was more efficient compared to the other evaluated modifiers. It provided higher ion intensities to the majority of analytes. Doehlert experimental design allowed finding a region indicative of the optimum experimental conditions for most analytes. The best experimental condition observedwas 3.5mMammoniumhydroxide concentration; 0.0917 mL/min of mobile phase; 300 °C heating block temperature; and drying gas at 200 kPa. These optimized parameters resulted in decreased detection limits of the method. The optimized method was applied to the evaluation of water samples coming from the Rio Doce basin — Minas Gerais/Brazil utilizing multivariate exploratory techniques such as principal component analysis and Kohonen neural network. In this way, the use of chemometric approach showed to be a promisingway to optimize the simultaneous determination of twentyone contaminants of emerging concern in aqueous matrices by LC-IT-TOF-HRMS using ESI.Item Descriptive screening and lexicon development of non-aged artisanal cachaça sensorial profile using principal component analysis and Kohonen artificial neural networks.(2021) Caetano, Daniela; Lima, Clara Mariana Gonçalves; Sanson, Ananda Lima; Silva, Débora Faria; Hassemer, Guilherme de Souza; Verruck, Silvani; Silva, Gilmare Antônia da; Afonso, Robson José de Cássia Franco; Coutrim, Maurício Xavier; Gregório, Sandra ReginaCachaça is a distilled spirit made from sugarcane, exclusively produced in Brazil, and appreciated worldwide. This paper seeks to evaluate the sensory characteristics of 24 nonaged artisanal cachaça samples from Salinas (Minas Gerais, Brazil) through descriptive analysis, as well as chemometrically treat the obtained data based on prin- cipal components analysis (PCA) and Kohonen's neural network. The attributes (23) were divided between aroma (11) and flavor (12). PCA does not show good dif- ferentiation of nonaged cachaça samples. On the other hand, by using Kohonen's neural network it was possible to group samples according to their aroma and flavor characteristics in 9 and 10 distinct groups, respectively. A reduced number of descriptors could be used to describe the flavor of cachaça samples (alcohol, acidic, sweet, bitter, citric, tar, and burning), as significant correlations (R > 0.70, p < .05) exist among them with fruity, bagasse, fermented sugarcane juice, and astringent descriptors. This diminution on descriptors numbers could be able to reduce the workload of the judging panel with no losses to the sample' sensory characterization. The use of Kohonen's network chemometric treatment for treat sensory data showed to be a better alternative that PCA approach in this study.Item Desenvolvimento de métodos baseados na extração com partição à baixa temperatura para determinação simultânea de antibióticos em matrizes de estações de tratamento de esgoto por HPLC-MS/MS.(2021) Cunha, Camila Cristina Rodrigues Ferreira da; Afonso, Robson José de Cássia Franco; Sanson, Ananda Lima; Afonso, Robson José de Cássia Franco; Queiroz, Maria Eliana Lopes Ribeiro de; Brandt, Emanuel Manfred Freire; Faria, Adriana Ferreira; Aquino, Sergio Francisco de; Baeta, Bruno Eduardo LoboA ocorrência de antibióticos em matrizes ambientais constitui uma potencial ameaça à saúde pública, uma vez que contribui para a o desenvolvimento e disseminação da resistência bacteriana. Dessa forma, a determinação do nível de contaminação dos antibióticos e seu lançamento no meio ambiente, particularmente pelos sistemas de tratamento de esgotos, são de fundamental importância para apoiar estudos de investigação do perfil de resistência bacteriana. Neste trabalho, métodos analíticos foram desenvolvidos e validados baseados na extração por partição em baixa temperatura (LTPE) seguida por cromatografia líquida de alta eficiência acoplada à espectrometria de massas (HPLC-MS/MS) para a determinação multiclasse de antibióticos em matrizes complexas de estação de tratamento de esgoto (ETE), o qual inclui o esgoto bruto, tratado e o lodo anaeróbio. Os antibióticos analisados no esgoto foram: amoxicilina, cefalexina, sulfametoxazol, sulfadiazina, trimetoprima, ciprofloxacina, norfloxacina, levofloxacina e eritromicina, enquanto que para a matriz de lodo de esgoto foram: sulfametoxazol, sulfadiazina e trimetoprima. A quantificação dos antibióticos foi realizada pelo método da dupla injeção consecutiva, sem o uso de calibração interna com compostos marcados, a fim de corrigir os efeitos de matriz. Para a matriz de esgoto, os parâmetros avaliados e otimizados na LTPE foram: pH da amostra, razão volumétrica entre amostra e o solvente extrator, tempo de extração em banho ultrassônico, material do tubo de extração, solvente e volume para reconstituir os extratos da amostra. Adicionalmente, a influência dos sólidos presentes na matriz de esgoto foi avaliada. Amostras de esgoto na sua forma integral, incluindo as frações líquidas e sólidas do esgoto foram analisadas. Os resultados revelaram que a etapa de filtração, usualmente utilizada em várias técnicas de extração de analitos em amostras ambientais complexas, pode subestimar a concentração total de antibióticos presentes, principalmente, para os compostos hidrofóbicos que possuem maior afinidade pelos sólidos. O limite de detecção do método variou de 18,54 ng L-1 (trimetoprima) à 78,49 ng L-1 (ciprofloxacina), exceto para a amoxicilina que apresentou um limite de detecção maior (235,80 ng L-1 ). Precisão intradia (coeficiente de variação) menor do que 12,3% foi alcançada. Os valores de recuperação variaram de 13,9 (sulfadiazina) à 48,9% (eritromicina) nas amostras de esgoto bruto e de 19,1% (sulfadiazina) a 57,2% (ciprofloxacina) nas amostras de esgoto tratado. Na matriz de lodo de esgoto, avaliou-se a influência das seguintes variáveis no procedimento de extração: massa seca (ms) de lodo de esgoto, tempo de extração em banho ultrassônico, pH da solução tampão e número de ciclos de extração. Os limites de detecção do método variaram de 3,66 ng g-1 ms (trimetoprima) à 11,37 ng g-1 ms (sulfametoxazol). A precisão intradia alcançada foi menor do que 18,9%. Os valores de recuperação variaram de 29,1% (sulfadiazina) à 70,6% (trimetoprima). Os métodos desenvolvidos e validados foram aplicados para a determinação multirresíduo de antibióticos em esgoto bruto, tratado e lodo de esgoto. Seis dos nove antibióticos investigados foram detectados no esgoto bruto e cinco foram encontrados no esgoto tratado. Já no lodo de esgoto, apenas a trimetoprima foi detectada. O trabalho fornece uma nova compreensão sobre a aplicabilidade de LTPE para extração de resíduos de antibióticos de esgoto e lodo de esgoto.Item Determinação de carbamato de etila em aguardentes de cana por CG-EM.(2008) Labanca, Renata Adriana; Glória, Maria Beatriz Abreu; Afonso, Robson José de Cássia FrancoA simple, specific and sensitive GC-MS procedure with ion m/z 62 was validated for the determination of ethyl carbamate (EC) in spirits. It exhibited linearity over the concentration of 30 to 600 μg/L with 30 μg/L limit of quantification. EC was detected in 70 of the 71 samples analyzed with levels from 33 to 2609 μg/L (mean level = 893 μg/L). 35% of the samples contained 500 to 1000 μg/L and 23% contained 150 to 500 and 1000 to 1500 μg/L. No significant correlation was found between EC and the levels of copper, pH and alcohol content of the samples.Item Determinação dos teores de cobre e grau alcoólico em aguardentes de cana produzidas no estado de Minas Gerais.(2006) Labanca, Renata Adriana; Glória, Maria Beatriz Abreu; Gouveia, Vitor José Pinto; Afonso, Robson José de Cássia FrancoThe objective of this work was to investigate if producers of sugar cane spirits in Minas Gerais, Brazil, have improved the copper content of their products and also if they have adjusted to the new standards of identity for ‘cachaça’ and ‘aguardente’. Seventy-one samples, obtained from May 2003 until March 2004, were analyzed. Mean copper content was 2.30 mg/L, which indicates a significant reduction in levels. The mean alcohol content was 45.6 % v/v. All of the ‘aguardente’ but only 79% of the ‘cachaça’ attended to the standard of identity for alcohol content for these products.Item Determination of endocrine disrupters and pharmaceuticals in sewage samples by tandem solid phase clean up/extraction and high performance liquid chromatography-negative and positive electrospray high-resolution mass spectrometry.(2014) Queiroz, Fernanda Barbosa de; Silva, Júlio César Cardoso da; Aquino, Sergio Francisco de; Coutrim, Maurício Xavier; Afonso, Robson José de Cássia FrancoFoi desenvolvido e validado um método para determinação de três perturbadores endócrinos (estradiol, etinilestradiol e bisfenol A) e cinco produtos farmacêuticos (sulfametoxazol, trimetoprima, diclofenaco, bezafibrato e miconazol) em amostras de esgoto bruto, utilizando extração em fase sólida (SPE) e cromatografia líquida à espectrometria de massas em alta resolução (HPLC-HRMS) com ionização por eletrospray, nos modos positivo e negativo. Foi utilizado na extração em fase sólida um cartucho de troca iônica forte (Strata SAX) e um cartucho contendo divinilbenzeno-pirrolidona, para reduzir os níveis dos alquilbenzeno-sulfonados de cadeia linear (LAS) e para concentrar os analitos de interesse das amostras de esgoto. A influência do efeito matriz na eficiência da ionização, a recuperação da EFS e a sensibilidade do método foi identificada e quantificada. O método foi aplicado com sucesso na determinação dos analitos em amostras de esgoto coletadas na entrada da estação de tratamento de efluentes (ETE) do Arrudas em Belo Horizonte, MG, Brasil.Item Determination of nine pharmaceutical active compounds in surface waters from Paraopeba River Basin in Brazil by LTPE-HPLC-ESI-MS/MS.(2018) Barros, André Luis Corrêa de; Schmidt, Felix Florian; Aquino, Sergio Francisco de; Afonso, Robson José de Cássia FrancoA simple, inexpensive, versatile, and environment-friendly extraction method, using low-temperature partitioning extraction (LTPE), was validated to quantify pharmaceutical-active compounds (PhACs) in surface water samples by high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The PhACs analyzed were acetaminophen, bezafibrate, diclofenac, diltiazem, fluconazole, linezolid, miconazole, ondansetron hydrochloride, and trimethoprim. The detection and quantification limits ranged from 0.15 to 12.30 ng L−1 and 0.43 to 40.60 ng L−1, respectively. Recovery rates ranged from 46 to 135%, and relative standard deviation (RSD%) varied between 0.49 and 6.13%. This method was applied to monitor water contamination by PhACs in the Paraopeba River Basin (PRB), Minas Gerais state, Brazil. All PhACs, except linezolid which was not detected, were found in PRB water samples in concentrations that ranged from 2.6 ng L−1 to 2.62 μg L−1.Item Effect of cooking method on the formation of 7-ketocholesterol in Atlantic hake (Merluccius hubbsi) and smooth weakfish (Cynoscion leiarchus) fillets.(2015) Freitas, Maria Tereza de; Amaral, Cláudia Antônia Alcântara; Coutrim, Maurício Xavier; Afonso, Robson José de Cássia Franco; Junqueira, Roberto GonçalvesThe levels of cholesterol and 7-ketocholesterol were measured in raw Atlantic hake (Merluccius hubbsi) and smooth weakfish (Cynoscion leiarchus) fillets and in fillets subjected to the following cooking methods: baking in an electric or microwave oven; baking, grilling or stewing in a steam-convection oven; simmering on a stove; electric grilling; and deep frying. The raw samples from both fishes exhibited significantly (p < 0.05) higher cholesterol levels (62.71 ± 6.06 mg/100 ge74.16 ± 3.96 mg/ 100 g) than the processed fillets. In all of the samples, 7-ketocholesterol was detected at significantly (p < 0.05) different levels depending on the cooking method and the type of fish. Steam cooking keeping the surface of the product moist produced small decrease in the cholesterol content (26.65%e29.96%) and a low level of 7-ketocholesterol in the samples (6.90 ± 0.21 mg/ge6.47 ± 0.28 mg/g). Baking in electric or steam-convection ovens at high temperatures and long times greatly reduced the cholesterol content (52.77%e65.08%), which was associated with a large increase in 7-ketocholesterol levels (11.54 ± 0.45 mg/ge13.94 ± 1.17 mg/g). These results indicate the necessity of revising the baking procedures for fish to increase the healthiness of food.
- «
- 1 (current)
- 2
- 3
- »