VALIDAÇÃO DE METODOLOGIAS ANALÍTICAS PARA A QUANTIFICAÇÃO DE METAIS (Cu, Fe, Mn e Zn) EM TECIDO ANIMAL POR FAAS

Abstract

Essential metals are important in the normal functioning of the body, but when there is deficiency or excess of these elements, the body can not complete its normal cycle and / or healthy growth. In the literature there are studies that describe what essential elements may be related to the appearance of neoplasms. Typically, the methodologies found in the literature for the digestion of biological tissues are time consuming and use high amounts of reagents. Therefore, it is important to develop fast and cost-effective analytical methodologies for the determination of metals in biological samples, in order to relate the concentration of these metals to the appearance of neoplasms. The objective of this work was to optimize and validate analytical methodologies for the quantification of Cu, Fe, Mn and Zn in animal tissues with and without neoplasms using the Flame Atomic Absorption Spectrometry (FAAS) technique. Two sample preparation methods were evaluated, acid digestion using HNO3 and alkaline solubilization of tissues using Tetramethylammonium (TMAH) both using digester block. The analytical validation study was evaluated by the parameters of linearity, limits of detection and quantification, precision and accuracy. The time required for the acid digestion was 1:30 h and for alkaline solubilization it was 1:00 h. The recoveries obtained in the acid digestion were 105.5% for Cu, 103.3% for Fe, 94.9% for Mn and 89.6% for Zn, in the alkaline solubilization were 100.8% Cu, 98, 7% for Fe, 103.7% for Mn and 95.7% for Zn, all recoveries were adequate for the concentration range studied. After validation of the two analytical methodologies, it was decided to apply alkaline solubilization in 31 samples of biological tissues (breast, pancreas, skin and canine testicles) with and without neoplasms in Cu, Fe, Mn and Zn quantification. Significant differences in metal concentrations were observed in many samples when comparing healthy tissue with neoplastic tissue, but these differences did not follow a defined pattern. A Principal Component Analysis (PCA) indicated that there is a correlation between Fe and Cu in the samples evaluated. It also pointed out that the testis tissues have higher concentrations of Zn, whereas the breast tissues correlated with the higher levels of Fe and Cu. The skin and pancreas samples had no definite correlation with any of the metals.