RESUMO
In the present study, a simple, rapid and sensitive method was developed for the determination of mercury concentrations in the muscle tissue of fish from the Brazilian Amazon using graphite furnace atomic absorption spectrometry (GFAAS) following acid mineralization of the samples in an ultrasonic cold water bath. Using copper nitrate as a chemical modifier in solution and sodium tungstate as permanent modifier, we were able to attain thermal stabilization of the mercury up to the atomisation temperature of 1600 °C in the GFAAS assay. The calculated limits of detection (LOD) and quantification (LOQ) were 0.014 and 0.047 mg kg(-1), respectively.
Assuntos
Mercúrio/análise , Músculo Esquelético/química , Alimentos Marinhos/análise , Espectrofotometria Atômica/métodos , Animais , Brasil , Peixes , Contaminação de Alimentos/análise , Limite de DetecçãoRESUMO
This paper presents preliminary findings for a metallomics study of mercury in the muscle of the fish species from Amazonas, Brazil, after protein separation by two-dimensional polyacrylamide gel electrophoresis and subsequent evaluation of mercury by synchrotron radiation X-ray fluorescence. The fluorescence spectra revealed mercury in two protein spots. The mercury-containing protein spots showed molecular weights of 20.8 ± 0.7 and 19.8 ± 0.5 kDa and isoelectric points of 5.6 ± 0.2 and 7.5 ± 0.3, respectively.
Assuntos
Peixes-Gato/metabolismo , Characidae/metabolismo , Exposição Ambiental , Proteínas de Peixes/análise , Mercúrio/toxicidade , Músculos/química , Poluentes Químicos da Água/toxicidade , Animais , Biomarcadores/análise , Biomarcadores/química , Biomarcadores/metabolismo , Brasil , Peixes-Gato/crescimento & desenvolvimento , Characidae/crescimento & desenvolvimento , Eletroforese em Gel Bidimensional , Exposição Ambiental/efeitos adversos , Monitoramento Ambiental/métodos , Proteínas de Peixes/química , Proteínas de Peixes/metabolismo , Ponto Isoelétrico , Mercúrio/análise , Mercúrio/farmacocinética , Metaloproteínas/análise , Metaloproteínas/química , Metaloproteínas/metabolismo , Peso Molecular , Proteínas Musculares/análise , Proteínas Musculares/química , Proteínas Musculares/metabolismo , Músculos/metabolismo , Proteômica/métodos , Rios , Espectrometria por Raios X , Síncrotrons , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/farmacocinéticaRESUMO
The purpose of this work was to determine the concentration of copper in samples of farmed Nile tilapia (Oreochromis niloticus L.) fillets purchased in the city of Botucatu (São Paulo, Brazil) and in fillet and liver samples of Tilapia fed diets supplemented with different concentrations of Cu from the Laboratory of Aquatic Organism Nutrition/FMVZ-UNESP (Botucatu, Brazil). The fillet samples were prepared by lyophilisation and cryogenic grinding into particles smaller than 60 µm, and copper was extracted ultrasonically using 0.10 mol l(-1) HCl as extraction solution. Copper determination was performed by graphite furnace atomic absorption spectrometry (GFAAS) with optimised temperatures of drying, pyrolysis, atomisation and cleaning. Palladium nitrate was injected into the samples as a chemical modifier and tungsten as a permanent modifier. Copper concentrations of 0.70-1.60 mg kg(-1) were found, which are in line with Brazilian regulations. The accuracy and precision of the copper concentrations determined in this study were evaluated using certified standard Lake Michigan fish tissue (NIST SRM 1947).
