Produção de Materiais de Referência Para Nutrientes e Contaminantes Inorgânicos em Amostras de Ração e Tecido de Peixe

Abstract

In order the facilitate the growth of the Brazilian fishery production, in a sustainable way, it is necessary to develop sound scientific and technological base to address the existing demands in the various links of the production chain. One of the main evidences of the products' quality is provided by the analytical results, whose reliability and accuracy can be assured by the use of reference materials (RM). In this context, it was produced a RM of fish feed for macro-and micronutrients and proximates analysis. Also, a RM of fish tissue, which is in its final stage of development, for nutrients and inorganic contaminants. The production of reference materials followed the ISO Guides 30-35 standards: preparation and packaging, irradiation, minimum sample, homogeneity, short-and long-term stability, and material characterization. The materials were acquired from commercial suppliers. The materials were dried/freeze-dried, pulverized, homogenized and aliquoted into amber glass bottles. The bottles were gamma irradiated to a minimum dose to inhibit bacterial action. Characterization of the candidate fish feed RM was performed through a round robin exercise. The study of minimum sample mass, homogeneity and stability of the material were performed using inductively coupled plasma optical emission spectrometry (ICP-OES). Results from sub-samples (250 mg) were evaluated and it was verified that the fish feed proposed RM could be considered homogeneous for Ca, Cu, Fe, Mg, Mn and Na, as no significant difference in significance level of 0.05 was observed. Long-term stability study of this proposed RM was performed by the residual analysis in regression and ANOVA and the short-term stability study was performed by simple linear regression. This proposed RM could be considered sufficiently stable to be stored at room temperature. The data obtained along the production and through the round robin exercise allowed the characterization of the fish feed RM as well the determination of uncertainties components. For the proposed RM of fish tissue, Inductively coupled plasma mass spectrometry (ICP-MS) was also used for the assessment of homogeneity and short-term stability. Results from sub-samples (250 mg) were evaluated and considered homogeneous and stable to be transported under temperature below 37ºC.