Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Chemosphere ; 183: 27-35, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28531556

RESUMO

Mercury concentrations were investigated in freshwater sediment from two canals in Scotland, UK. High concentrations found in the Union Canal (35.3-1200 mg kg-1) likely originate from historical munitions manufacture, with lower levels in the Forth & Clyde Canal (0.591-9.14 mg kg-1). Concentrations of methylmercury (MeHg) were low - from 6.02 to 18.6 µg kg-1 (0.001-0.023% of total Hg) in the Union Canal and from 3.44 to 14.1 µg kg-1 (0.11-0.58% of total Hg) in the Forth & Clyde Canal - and there was a significant inverse relationship between total Hg concentration and %MeHg. Total Hg concentration was significantly negatively correlated with pH and positively correlated with Fe content (in the Union Canal only) but not with organic matter, S content or the proportion of clay present. The MeHg concentration was not correlated with any of the above sediment parameters. Ethylmercury was detected in the most highly contaminated sediments from the Union Canal.


Assuntos
Monitoramento Ambiental/métodos , Água Doce/química , Sedimentos Geológicos/química , Mercúrio/análise , Compostos de Metilmercúrio/análise , Poluentes Químicos da Água/análise , Alquilação , Mercúrio/química , Compostos de Metilmercúrio/química , Escócia , Poluentes Químicos da Água/química
2.
J Chromatogr A ; 1218(28): 4545-51, 2011 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-21641604

RESUMO

In this study, we evaluate advantages and disadvantages of three hyphenated techniques for mercury speciation analysis in different sample matrices using gas chromatography (GC) with mass spectrometry (GC-MS), inductively coupled plasma mass spectrometry (GC-ICP-MS) and pyrolysis atomic fluorescence (GC-pyro-AFS) detection. Aqueous ethylation with NaBEt(4) was required in all cases. All systems were validated with respect to precision, with repeatability and reproducibility <5% RSD, confirmed by the Snedecor F-test. All methods proved to be robust according to a Plackett-Burnham design for 7 factors and 15 experiments, and calculations were carried out using the procedures described by Youden and Steiner. In order to evaluate accuracy, certified reference materials (DORM-2 and DOLT-3) were analyzed after closed-vessel microwave extraction with tetramethylammonium hydroxide (TMAH). No statistically significant differences were found to the certified values (p=0.05). The suitability for water samples analysis with different organic matter and chloride contents was evaluated by recovery experiments in synthetic spiked waters. Absolute detection and quantification limits were in the range of 2-6 pg for GC-pyro-AFS, 1-4 pg for GC-MS, with 0.05-0.21 pg for GC-ICP-MS showing the best limits of detection for the three systems employed. However, all systems are sufficiently sensitive for mercury speciation in environmental samples, with GC-MS and GC-ICP-MS offering isotope analysis capabilities for the use of species-specific isotope dilution analysis, and GC-pyro-AFS being the most cost effective alternative.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Compostos de Mercúrio/análise , Animais , Boratos , Cação (Peixe) , Modelos Lineares , Fígado/química , Compostos de Mercúrio/química , Músculos/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectrometria de Fluorescência , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química
3.
Chem Commun (Camb) ; (28): 4257-9, 2009 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-19585039

RESUMO

The molecular structure of a variety of novel mercury-phytochelatin complexes was evidenced in rice plants exposed to inorganic mercury (Hg2+) using RP-HPLC with simultaneous detection via ICP-MS and ES-MS.


Assuntos
Espectrometria de Massas/métodos , Mercúrio/química , Peptídeos/química , Plantas/química , Cromatografia Líquida de Alta Pressão , Estrutura Molecular
4.
Fresenius J Anal Chem ; 370(5): 573-80, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11496989

RESUMO

The precision and accuracy of lead isotope-ratio determination on a short transient signal has been assessed by coupling capillary gas chromatography to the Isoprobe (Micromass, UK), a single-focusing inductively coupled plasma mass spectrometer with multicollector detection. A T-piece connecting the GC transfer line to the torch enabled continuous aspiration of thallium solution for mass-bias correction. The volatile lead species PbEt4 was derivatized from NIST isotopic certified lead standard SRM 981 and different amounts of PbEt4 dissolved in iso-octane were injected into the GC. Chromatograms were recorded in multicollection mode by use of Faraday cups; seven isotopes (204Pb, 206Pb, 207Pb, 208Pb,

5.
Anal Bioanal Chem ; 354(5-6): 546-9, 1996 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15067443

RESUMO

Low temperature GC on-line coupled with an ICP/MS has been used as analytical device to detect organometallic and -metalloid compounds from various sediments of rivers and harbours in West Germany. The different species have been volatilized by derivatization with NaBH(4) and cryofocussed in a trap. Different alkylated species of As, Sn and Sb have been identified, while only methylated compounds of the elements Ge, Se, Te, Hg and Bi could be detected.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA