2,844 research outputs found
Desenvolvimento e validação de método multirresíduos para determinação de resíduos de agrotóxicos em pólen apícola por GC-MS/MS ÍON TRAP.
Métodos de extração de hidrocarbonetos policíclicos aromáticos em amostra de solo, sedimento e lodo.
bitstream/item/12265/1/documentos_79.pd
Residues of mancozeb, glyphosate, copper and manganese in Isabella grape juice and wine made from grapevines cultivated under conventional and organic systems.
Antigenic expression in human choroid plexus carcinoma : report of two cases
Neoplasias provenientes do epitélio de revestimento do plexo coróide são inco-muns, tendo sido descritos 6 padrões morfológicos. O padrão anaplásico, também denominado carcinoma do plexo coróide, é o de menor freqüência e pode dar metastases fora do SNC. A distinção histológica desses tumores, particularmente da variedade anaplásica, com outras neoplasias primárias e metastáticas no SNC pode ser difícil. O uso de técnicas imunocitoquimicas em parafina tem-se mostrado útil no esclarecimento das linhagens tumorais. Os papilomas do plexo coróide têm, no entanto, sido objeto de controvérsia, por sua complexa expressão antigênica. Usando a técnica de imunoperoxidase (sistema avidina-biotina-peroxidase) pesquisaram-se, em dois casos da variedade anaplásica, os seguintes marcadores: proteína glial fibrilar ácida (GFAP) com anticorpo monoclonal e policlonal; ceratinas de 40-50kDa, ceratinas de 60-70kDa (callus ceratina), enolase neuronal específica (NSE) e proteína S-100, com anticorpos monoclonais. Os dois tumores mostraram positividade para NSE, proteína S-100 e ceratina de 40-50kDa; uma das duas neoplasias mostrou diferenciação glial, revelando positividade para GFAP tanto com anticorpo monoclonal quanto policlonal.Primary neoplasms of choroid plexus are rare. Six morphological variants have been described: papillary, cystic, acinar, mucus-secreting, oncocytic, and anaplastic. The anaplastic variant, the so-called choroid plexus carcinoma, is the rarest of all and can metastasize. The differential diagnosis of the anaplastic variant of choroid plexus neoplasms with adenocarcinomas, melanomas and indifferentiated neoplasms can be troublesome chiefly in adults. The now large use of immunocytochemical techniques in tissue section has become a powerful tool in the analysis of cell lineages, tumoral and non-tumoral. Nevertheless, the choroid plexus neoplasms have shown a complex and a somewhat confusing pattern of antigenic expression. In two choroid plexus carcinomas (one localized in the right lateral ventricle from a boy of 1 year and 9 months old, and the other localized in the left lateral ventricle from a girl of 3 years old) the following antigens were searched (using the avidin-biotin-peroxydase complex): glial fibrillary acidic protein (GFAP) with monoclonal and polyclonal antibodies; cytokeratins of 40-50kDa, cytokeratins of 60-70kDA (callus cytokeratin), neuronal specific enolase (NSE) and S-100 protein with monoclonal antibodies. The two neoplasms showed immunoreactivity against NSE, S-100 protein and cytokeratin of 40-50kDA The neoplasm of the boy exhibited glial differentiation having immunoreactivity against GFAP with monoclonal and polyclonal antibodies
DETERMINATION OF PESTICIDES IN WATER BY LIQUID CHROMATOGRAPHY-(ELECTROSPRAY IONIZATION)-MASS SPECTROMETRY (LC-ESI-MS)
Desenvolveu-se método para a determinação de selecionado grupo de pesticidas em água (de torneira e subterrânea),
usando cromatografia em fase líquida (ionização do tipo electrospray) espectrometria de massas (CL-IE-EM). Os pesticidas
dimetoato, carbaril, simazina, atrazina, ametrina, tebutiuron, diuron e linuron foram isolados por meio de extração líquidolíquido
com diclorometano e analisados em coluna de fase reversa, tipo C-18, com eluição por gradiente e vazão de
1 mL min-1. Foram obtidas recuperações nas faixas de 89% a 112% (R.S.D. ≤ 10%) para água de torneira e de 76 a 98%
(R.S.D. ≤ 6%) para água subterrânea. O procedimento de enriquecimento, que pré-concentra amostras em 500 vezes,
seguido do uso de monitoramento seletivo de íon (modo SIM) forneceu limite de quantificação suficientemente baixo para
atender a legislação internacional (0,1 µg.L-1). O método desenvolvido mostrou-se prático, eficiente e confiável para a
determinação dos pesticidas selecionados em amostras de água.
DETERMINAÇÃO DE PESTICIDAS EM ÁGUA POR CROMATOGRAFIA EM FASE LÍQUIDA (IONIZAÇÃO DO
TIPO ELECTROSPRAY)-ESPECTROMETRIA DE MASSAS (CL-IE-EM)
Abstract
A method for determination of a selected group of
pesticides in water (tap and ground water) was
developed using liquid chromatography-(electrospray
ionization)-mass spectrometry (LC-ESI-MS). The
pesticides dimethoate, carbaryl, simazine, atrazine,
ametryne, tebuthiuron, diuron and linuron were
isolated using liquid-liquid extraction with
dichloromethane and analyzed on a reversed phase
column, C-18, with gradient elution at flow rate of
1 mL. min-1. Recoveries ranged from 89% to 112%
(R.S.D. ≤ 10%) for tap water and from 76% to 98%
(R.S.D ≤ 6%) for ground water. The enrichment
procedure, followed by use of the selected ion
monitoring (SIM) mode gave quantification limits low
enough to reach the international legislation level of
0.1 µg.L-1, with a 500-fold preconcentration. The
method developed is practical, efficient and reliable
for the determination of the selected group of
pesticides in the water samples
Physicochemical composition, minerals, and pesticide residues in organic grape juices.
Demand for organic products is intensified in many countries each year. Following this trend, Brazil produces increasing volumes of organic grape juice. In this way, a survey of organic grape juices made from grapes produced according to this system was carried out where physicochemical composition, minerals, trace elements, and pesticide residues were determined. Variables related to grape juice composition were performed by physicochemical procedures; minerals and trace elements, by inductively plasma optical emission spectrometry; pesticide residues, by liquid chromatography-mass spectrometry. Main results show that the physicochemical composition of organic grape juices was in general in accordance to the Brazilian legislation. The mean concentrations of trace elements were very low, varying from 0.002 (Cd) to 0.970 (Ba) mg L?1. Pesticide residues were not detected in any sample analyzed (MRL= 10 μg L?1). These results show that the Serra Gaúcha viticultural region present conditions to produce organic grape juices, despite the adverse climate factors that occurs in some years. Nevertheless, these products should be made with grape varieties, such as the labrusca ones, less susceptibles to the main grapevine pathogens
Novos sorventes baseados em Poli(Metiloctilsiloxano) sobre sílica para uso em extração em fase sólida.
This paper presents an easy and practical procedure to obtain silica-based C-8 type sorbents for use in solid-phase extraction. The materials are prepared by depositing poly(methyloctylsiloxane), PMOS, on the silica support. Two different treatments for immobilization were used: thermal treatment or gamma irradiation. Suitable recoveries were obtained after pre-concentration of dilute solutions, at the ng/L level, of a mixture of pesticides, indicating the good performance of the materials
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