Desenvolvimento e validação de método para determinação de arsênio total em ração, sais minerais e suplementos de alimentação animal por espectrometria de absorção atômica com geração de hidretos

Abstract

This study was carried out the optimization and validation of a method for the determination of total arsenic using acid digestion in an open flask. Quantification was performed by hydride generation coupled to atomic absorption spectrometry – HG-ASS. The technique proved to be promising for the investigation of arsenic in the seven matrices: phosphate and calcareous seaweed; carbonates and limestone marine shells; magnesium oxides and magnesium carbonate; copper and ferrous carbonate salts; zinc, manganous and cupric oxides; premix and animal feed. The optimization of the sample preparation and instrumental was performed through multivariate analysis. There was no matrix effect for the proposed method, which allowed the analyte to be quantified in different matrices using the same analytical curve. The LOQ were 2.0; 3.0; 6.0; 10; 20; 2.0 e 0.4 mg kg-1 for phosphate and carbonated matrices, magnesium oxides, sulfated matrices, zinc oxides, mineral mixture and feed, respectively. All limits correspond to one fifth of the allowed limit under Brazilian law, and in the international agreement signed with the European Union, except for magnesium oxide matrix. The recovery of the method varied from 88-98%, at the concentration levels corresponding to the maximum residue limit. All uncertainty values are following the legislation, as they maintained an agreement with the recommended allowed uncertainty limit.