Desenvolvimento de procedimentos analíticos para a determinação de mercúrio em peixe baseado na extração empregando banho ultrassônico, geração de vapor frio e análise espectrofotométrica do complexo HgI42-

Abstract

Mercury is a liquid metal at room temperature and is toxic to all species found in nature. This element is largely emitted by anthropogenic sources, such as mining, and by natural emission sources, such as volcanoes. The metal forms stable covalent bonds (sharing electrons) with carbon atoms, thus, there is a wide variety of organometallics of this metal. These organic mercury compounds are the most toxic. The metal is found in all environments of nature: hydrosphere, lithosphere, atmosphere and biosphere. In addition, it is also found in some species that are part of the human diet, as it is a toxic element, the consumption of foods that contain this metal must be controlled. The World Health Organization (WHO) recommends a maximum methyl mercury intake of 1.6 μg kg-1 per week. The WHO also states that the accepted safe limits for contamination of fish with mercury (in the form of methyl mercury) is 0.5 ppm. With the great use of Hg and its disposal in the environment by anthropic activities, it is surely incorporating the element into the geochemical cycles and trophic chains of animals, increasing its concentrations in the ecosystem. Its determination and quantification in biological tissues is extremely important. Currently, there are several analytical methodologies for the detection and quantification of metal, however they are complex methodologies with equipment that is difficult to acquire. Thus, the work presented aims to develop analytical procedures for spectrophotometric determination of mercury in fish samples. In this way, a procedure using an ultrasonic bath and the generation of cold mercury vapor will be explored to extract this metal from fish samples, which are procedures widely used for some analysis methodologies. After the extraction, the spectrophotometric determination will be explored by the formation of the HgI42- complex, a complex that presents UV absorption that has been little explored quantitatively.