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

Development of solid-phase extraction for triazines: application to a biological sample.

A sensitive extraction method for the triazines simazine, atrazine, and ametryn was developed and applied to a biological sample (urine). After protein precipitation with acetonitrile, a further purification using solid-phase extraction (SPE) was carried out. The samples were then analysed by high performance liquid chromatography (HPLC) usina a C18 column and an acetonitrile-water (40:60, v/v) mobile phase. The pH of the mobile phase was adjusted to 9.0 with NH4OH, the flow-rate was 0.5 mL/min and UV detection was at 220 nm. Recovery values were satisfactory and the method developed can be used for monitoring urine samples of workers exposed to simazine, atrazine, and ametryn, in forensic, veterinay, and environmental toxicologies

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

Determination of pesticides in water by liquid chromatography-(Electrospray Ionization)-mass spectrometry (LC-ESI-MS).

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. Um método para a determinação de um grupo selecionado de resíduos de pesticidas em água (de torneira e subterrânea) foi desenvolvido usando cromatografia líquida-ionização electrospray-espectrometria de massas (LC-ESI-MS). Os pesticidas dimetoato, carbaril, simazina, atrazina, ametrina, tebutiuron, diuron e linuron foram isolados usando extração líquido-líquido com diclorometano e analisados em uma coluna de fase reversa, C-18, com eluição gradiente a uma vazão de 1 mL/min. Foram obtidas recuperações de 89 a 112% (RSD <_10%) para água de torneira e 76 a 98% (RSD <_ 6%) para água subterrânea. O procedimento de enriquecimento, seguido pelo uso do monitoramento seletivo de íons (SIM) forneceu limites de quantificação baixos o suficiente para atingir a legislação internacional (Comunidade Européia) que é de 0,1 µg/L. O método desenvolvido é prático, eficiente e confiável para a determinação do grupo selecionado dos pesticidas em amostras de água

Application of new high-performance liquid chromatography and solid-phase extraction materials to the analysis of pesticides in human urine.

A method for the simultaneous determination of diuron and linuron pesticides in human urine was developed, using both solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) phases made in our own laboratory. These materials were prepared by sorption of polysiloxanes onto a silica surface, followed by immobilization. The HPLC columns were prepared from poly(methyloctylsiloxane), PMOS, immobilized onto silica with microwave radiation while the SPE cartridges where made with poly(methyloctadecylsiloxane), immobilized thermally. Method validation was performed for diuron and linuron for three fortification levels. The recoveries obtained were 85?103%, the inter- and intra-assay precisions were less than 1.6 and 1.8%, respectively. The limits of quantitation and detection for diuron were 2.4 and 8.0 ?g/l and for linuron were 5.0 and 12 ?g/l, respectively

Utilização de marcadores moleculares na seleção assistida para tolerância ao alumínio em sorgo.

bitstream/item/31669/1/circ-155.pd