RESUMEN
A method for the simultaneous determination of monomethylmercury (MeHg(+)) and monoethylmercury (EtHg(+)) in soil/sediment samples was developed. The method involves eluting mercury species from the soil/sediment samples using 5M HCl containing 5mM Pd(2+) and 0.1M Cu(2+) and then extracting MeHg(+) and EtHg(+) into toluene as chlorides. These alkylmercury chlorides are then back-extracted into an aqueous EDTA solution, creating EDTA complexes. Finally, an emetine-dithiocarbamate (emetineCS2) solution is added to the EDTA solution to form emetineCS2-alkylmercury complexes. EmetineCS2-MeHg and emetineCS2-EtHg were separated using reverse-phase HPLC and then detected by the chemiluminescence reaction with tris(2,2'-bipyridine)ruthenium(III). The MeHg(+) and EtHg(+) calibration curves, using the peak height, were linear from 0.5 to 20ng (as Hg). The detection limit was 0.16ng/g (analyzing 1g soil or sediment). The procedure was validated by analyzing a certified reference material (ERM CC580, estuarine sediment). The MeHg(+) concentration determined using the proposed method was in good agreement with the certified value, and EtHg(+) was detected in the reference material. A preliminary study of the relationship between environmental mercury concentrations and MeHg(+) production was performed.
Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Compuestos de Etilmercurio/análisis , Compuestos de Metilmercurio/análisis , Contaminantes del Suelo/análisis , Fraccionamiento Químico , Cromatografía de Fase Inversa/métodos , Compuestos de Etilmercurio/química , Compuestos de Etilmercurio/aislamiento & purificación , Sedimentos Geológicos/química , Mediciones Luminiscentes , Compuestos de Metilmercurio/química , Compuestos de Metilmercurio/aislamiento & purificación , Reproducibilidad de los Resultados , Suelo/química , Contaminantes del Suelo/química , Contaminantes del Suelo/aislamiento & purificaciónRESUMEN
A sensitive determination method for mercury speciation analysis was developed. Four mercury species, mercury ion, methylmercury, ethylmercury, and phenylmercury, were complexed with emetine-dithiocarbamate (emetine-CS(2)), and then injected onto a HPLC instrument coupled with a tris(2,2'-bipyridine)ruthenium(III) chemiluminescence detection system. The emetine-CS(2) complexing agent was effectively used to measure the concentration in addition to serving as a separation and detection reagent. The calibration curves for these mercury complexes were linear in the range of 0.050 - 10 µg L(-1) (as Hg). The limit of detection for (emetine-CS(2))(2)Hg, emetine-CS(2)-methylmercury, emetine-CS(2)-ethylmercury, and emetine-CS(2)-phenylmercury were 30, 17, 21, and 22 ng L(-1), respectively. The sensitivity of this method enables the determination of mercury species in water samples at sub-ppb levels. Furthermore, the method was applied to biological samples in combination with acid leaching and liquid-liquid extraction using emetine-CS(2) as an extraction reagent. The determination results were in good agreement with the values of the certified reference materials.
Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Contaminantes Ambientales/análisis , Mediciones Luminiscentes/métodos , Mercurio/análisis , Compuestos Organomercuriales/análisis , Agua/química , Animales , Contaminantes Ambientales/aislamiento & purificación , Compuestos de Etilmercurio/análisis , Compuestos de Etilmercurio/aislamiento & purificación , Peces , Cabello/química , Humanos , Mercurio/aislamiento & purificación , Compuestos de Metilmercurio/análisis , Compuestos de Metilmercurio/aislamiento & purificación , Compuestos Organomercuriales/aislamiento & purificación , Compuestos de Fenilmercurio/análisis , Compuestos de Fenilmercurio/aislamiento & purificaciónRESUMEN
This paper describes a preconcentration method for Hg(2+) and MeHg(+) in water samples using sodium diethyldithiocarbamate immobilized in polyurethane foam (PU-NaDDC) and an extraction method for several mercury species in sediment samples, including MeHg(+), EtHg(+) and PhHg(+), which is simple, rapid, and uses a single organic solvent. Separation and measurement were done by high-performance liquid chromatography on-line with inductively coupled plasma mass spectrometry (HPLC/ICP-MS). Initially, the test of recovery was applied using procedures compatible with HPLC. Under the optimum extraction conditions, recoveries of 96.7, 96.3 and 97.3% were obtained for MeHg(+), EtHg(+), and PhHg(+), respectively, from n=4 spiked sediment samples. This study also demonstrates that the combination of solid-phase extraction on PU-NaDDC with HPLC separation and ICP-MS detection is an effective preconcentration procedure for simultaneous measurement of Hg(2+) and MeHg(+) at ultra-trace levels in water samples. The application of the proposed procedure to the determination of mercury species in drinking water sample was investigated. The proposed method clearly gave satisfactory average recoveries between 93.7 and 101.5%.