Online solid phase extraction liquid chromatography tandem mass spectrometry (SPE-LC-MS/MS) method for the determination of sucralose in reclaimed and drinking waters and its photo degradation in natural waters from South Florida

Background Sucralose has gained popularity as a low calorie artificial sweetener worldwide. Due to its high stability and persistence, sucralose has shown widespread occurrence in environmental waters, at concentrations that could reach up to several μg/L. Previous studies have used time consuming sample preparation methods (offline solid phase extraction/derivatization) or methods with rather high detection limits (direct injection) for sucralose analysis. This study described a faster and sensitive analytical method for the determination of sucralose in environmental samples. Results An online SPE-LC–MS/MS method was developed, being capable to quantify sucralose in 12 minutes using only 10 mL of sample, with method detection limits (MDLs) of 4.5 ng/L, 8.5 ng/L and 45 ng/L for deionized water, drinking and reclaimed waters (1:10 diluted with deionized water), respectively. Sucralose was detected in 82% of the reclaimed water samples at concentrations reaching up to 18 μg/L. The monthly average for a period of one year was 9.1 ± 2.9 μg/L. The calculated mass loads per capita of sucralose discharged through WWTP effluents based on the concentrations detected in wastewaters in the U. S. is 5.0 mg/day/person. As expected, the concentrations observed in drinking water were much lower but still relevant reaching as high as 465 ng/L. In order to evaluate the stability of sucralose, photodegradation experiments were performed in natural waters. Significant photodegradation of sucralose was observed only in freshwater at 254 nm. Minimal degradation (\u3c20%) was observed for all matrices under more natural conditions (350 nm or solar simulator). The only photolysis product of sucralose identified by high resolution mass spectrometry was a de-chlorinated molecule at m/z 362.0535, with molecular formula C12H20Cl2O8. Conclusions Online SPE LC-APCI/MS/MS developed in the study was applied to more than 100 environmental samples. Sucralose was frequently detected (\u3e80%) indicating that the conventional treatment process employed in the sewage treatment plants is not efficient for its removal. Detection of sucralose in drinking waters suggests potential contamination of surface and ground waters sources with anthropogenic wastewater streams. Its high resistance to photodegradation, minimal sorption and high solubility indicate that sucralose could be a good tracer of anthropogenic wastewater intrusion into the environment

A High-Throughput Comet Assay Approach for Assessing Cellular DNA Damage

open access articleCells are continually exposed to agents arising from the internal and external environments, which may damage DNA. This damage can cause aberrant cell function, and therefore DNA damage may play a critical role in the development of, conceivably, all major human diseases, e.g., cancer, neurodegenerative and cardiovascular disease, and aging. Single-cell gel electrophoresis (i.e., the comet assay) is one of the most common and sensitive methods to study the formation and repair of a wide range of types of DNA damage (e.g., single- and double-strand breaks, alkali-labile sites, DNA-DNA crosslinks, and, in combination with certain repair enzymes, oxidized purines, and pyrimidines), in both in vitro and in vivo systems. However, the low sample throughput of the conventional assay and laborious sample workup are limiting factors to its widest possible application. With the "scoring" of comets increasingly automated, the limitation is now the ability to process significant numbers of comet slides. Here, a high-throughput (HTP) variant of the comet assay (HTP comet assay) has been developed, which significantly increases the number of samples analyzed, decreases assay run time, the number of individual slide manipulations, reagent requirements, and risk of physical damage to the gels. Furthermore, the footprint of the electrophoresis tank is significantly decreased due to the vertical orientation of the slides and integral cooling. Also reported here is a novel approach to chilling comet assay slides, which conveniently and efficiently facilitates the solidification of the comet gels. Here, the application of these devices to representative comet assay methods has been described. These simple innovations greatly support the use of the comet assay and its application to areas of study such as exposure biology, ecotoxicology, biomonitoring, toxicity screening/testing, together with understanding pathogenesis

EXTRACTION OF PERSISTENT ORGANOCHLORINE POLLUTANTS IN REMAINING FRAGMENTS OF MATA ATLÂNTICA, RJ: COMPARISON OF METHODS.

Persistent Organic Pollutants (POPs) are toxic substances of natural and anthropic origin that are ubiquitous pollutants in all environmental compartiments (soils, waters, air and biota). POPs have long half-lives in soils, sediments, air or biota and are hydrophobic and lipophilic. These characteristics confer persistence on the chemicals in biota, which accumulate a nd magnify in foodchains. POPs are normally stable and have the propensity to form a gas under appropriate environmental temperatures. Hence, they may volatilise from soil and contamined areas into the atmosphere. Because of their resistence to breakdown reactions in air, they can travel long distances (are subject to long-range atmospheric transport) before being re-deposited. Therefore, could acummulate in an area far removed from where they use or emmited. The Brazilian Environmental Legislation is still incipient regarding monitoring measures of the contamination and soil management. In this way, the main aim of this work was to perform a preliminary study to investigate the presence of the persistent organochlorine pollutants a and ß - HCH, lindane (?- HCH), alaclor, heptaclor, metolaclor, aldrin, endrin, dieldrin, a and ß endosulfan, DDT and isomers, in soils of remaining fragments of Mata Atlântica in the National Park of Serra dos Órgãos and in the region of Córrego Sujo catchment basins, tributary of Rio Preto. It was performed the extracion of POPs from soils using Soxhlet aparatus, ultrasound and microwave radiation energy, following by a cleanup step (C18 and/or Florisil) to eliminate matrix interferences, and further analysis by gas chromatography equipped with electon-capture detection (ECD) for identification and quantification of the POPs. The developed method for the determination of persistent organochlorine pollutants in soils was based in US-EPA recommended procedures and validated according to INMETRO instructions. It was obtained the detection and quantification limits for the instrument and method for the different soils matrix and extraction methodologies. Recoveries results obtained from spiked samples employing soxhlet, ultrasound and microowave assisted extraction methods showed values between 70 and 130 %, considered acceptable for trace analysis in environmental samples. It could be observed for some of the analyte recoveries values higher than 130 %, which can be related to matrix contribution, due to high organic carbon contents (8- 17 %). It was also performed a recovery study in certified reference material (ERM®- CC007) that showed good results. It was verified higher recoveries results when the microwave assisted extraction technique was used. In order to confirm the presence of analytes of interest in the analysed samples the exchange of estacionary phase was carried out. The obtained results showed low concentration of organochlorine compounds in the soils sampled in the studied areas. It could be concluded that this area is not considered of environmental concern.Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorEXTRAÇÃO DE POLUENTES ORGANOCLORADOS PERSISTENTES EM FRAGMENTOS REMANESCENTES DA MATA ATLÂNTICA, RJ: COMPARAÇÃO DE MÉTODOS. Poluentes orgânicos persistentes (POPs) são substâncias geradas por processos naturais e antrópicos que são encontrados em todos os compartimentos ambientais (solo, água, ar e biota). Os POPs tem meia-vida prolongada, são lipofílicos e hidrofóbicos. Essas características fazem com que esses compostos se acumulem e se magnifiquem na cadeia trófica. Os POPs são normalmente estáveis a degradação, mas podem volatilizar de solos e áreas contaminadas sob condições ambientais favoráveis. Devido a este fato, estão sujeitos ao transporte à longa distância, antes de serem novamente re-depositados. Conseqüentemente, podem acumular-se em áreas bem distantes de onde foram inicialmente usados ou emitidos. A Legislação Ambiental Brasileira ainda é bastante incipiente com relação às medidas de monitoramento da contaminação e gestão de solos. Apenas normas para disposição de resíduos estão disponíveis. Neste sentido, o trabalho desenvolvido teve por objetivo realizar um estudo preliminar sobre a presença dos poluentes organoclorados persistentes a e ß - HCH, lindano (?- HCH), alacloro, heptacloro, metolacloro, aldrin, endrin, dieldrin, a e ß endosulfan, DDT e seus isômeros em solos de fragmentos da Mata Atlântica (Parque Nacional da Serra dos Órgãos - PARNASO) e em uma Micro-Bacia da região Serrana do Rio de Janeiro (Micro-Bacia do Córrego Sujo contribuinte do Rio Preto), comparando-se métodos de extração distintos. Foi realizada a extração dos POPs do solo por Soxhlet, ultrasom e microondas, seguida de etapa de clarificação (C18 e/ou Florisil) dos extratos das amostras para eliminação de interferentes da matriz, para posterior análise por cromatografia a gás acoplada com detector de captura de elétrons (ECD) para a identificação e quantificação dos POPs. A metodologia desenvolvida para a determinação de poluentes organoclorados persistentes em solos foi baseada nos procedimentos da US-EPA e validada de acordo com orientações sobre validação de métodos de ensaio químico do INMETRO. Foram obtidos os limites de detecção e quantificação tanto para o instrumento quanto para o método, para as diferentes matrizes sólidas e métodos de extração. A recuperação dos organoclorados em matrizes fortificadas utilizando os métodos de extração por Soxhlet, ultrasom e microondas apresentaram valores compreendidos entre 70 e 130 %, considerados aceitáveis para a análise de resíduos orgânicos em amostras ambientais. Observou-se para alguns analitos recuperações acima de 130 %, o que pode ser atribuído à contribuição da matriz, que apresenta elevados teores de matéria orgânica (8- 17 %). Foi realizado o estudo de recuperação dos analitos em solo de referência certificado (ERM®- CC007), mostrando resultados satisfatórios. Verificou-se que a extração assistida por radiação microondas, por ser a técnica mais energética, apresentou maiores valores de recuperação. A confirmação do indicativo de presença dos analitos de interesse nas amostras foi obtida pela troca da fase estacionária. Os resultados obtidos mostraram que os solos, coletados nas diversas áreas de estudo, apresentaram baixas concentrações de agrotóxicos organoclorados, e por isso estas áreas não foram consideradas como impactadas

Novas abordagens sobre tratamentos da Leishmaniose tegumentar

De acordo com a Organização Mundial da Saúde, a leishmaniose é ainda uma das doenças mais negligenciadas do mundo, afetando principalmente países pobres e em desenvolvimento. As leishmanioses podem, de acordo com a forma de acometimento do homem, dividir-se em dois grandes grupos: visceral e tegumentar. As estatísticas mostram que cerca de 350 milhões de pessoas são consideradas com risco de contrair leishmaniose, e cerca de dois milhões de novos casos ocorrem anualmente. O número de casos de leishmaniose tegumentar no Brasil em 2011 foi de 15.731. É considerada uma doença negligenciada uma vez que os fármacos de escolha são preparações à base de antimoniais, sendo os mesmos desde sua descoberta em 1912. Além disso o tratamento é longo, doloroso e altamente tóxico, assim levando os pacientes muitas vezes a desistirem antes do término previsto. O presente trabalho tem como objetivo fazer uma revisão bibliográfica a partir do banco de dados do PubMed e Scielo sobre novas pesquisas na área de fármacos e novos tratamentos para leishmaniose cutânea entre os anos de 2007 e 2012