Artigo Publicado em Periódico
Slurry sampling and high-resolution continuum source flame atomic absorption spectrometry using secondary lines for the determination of Ca and Mg in dairy products
Fecha
2011-07Registro en:
0026-265X
v. 98, n. 2.
Autor
Brandão, Geovani Cardoso
Matos, Geraldo D.
Ferreira, Sergio Luis Costa
Brandão, Geovani Cardoso
Matos, Geraldo D.
Ferreira, Sergio Luis Costa
Institución
Resumen
The present paper proposes a simple and fast analytical procedure for the sequential multi-element
determination of Ca and Mg in dairy products employing sampling slurry and high resolution-continuum
source flame atomic absorption spectrometry (HR-CS FAAS). Considering the high concentration of these
species in these matrices, the analytical measurements were carried out at the secondary lines of 239.856 and
202.852 for Ca and Mg, respectively. The experimental conditions established for the preparation of the
slurries during the optimization step were: 2.0 mol L−1 hydrochloric acid, sonication time of 20 min and
sample mass of 1.0 g for a slurry volume of 25 mL. Experiments demonstrated that the analytical curves can be
established using the external calibration technique employing aqueous standards. The method allows the
determination of Ca and Mg with limits of quantification of 0.038 and 0.016 mg g−1, respectively. The
precision was evaluated under reproducibility and repeatability conditions and expressed as relative standard
deviation. The results varied from 2.7 to 2.9% (all tests with n=10) and using a yogurt sample containing Ca
and Mg concentrations of 1.40 and 0.13 mg g−1, respectively.
The accuracy was confirmed by the analysis of a certified reference material of non-fat milk powder furnished
by the National Institute of Standard and Technology. The proposed method was applied for the
determination of Ca and Mg in yogurt, cow milk and milk powder samples. The samples were also analyzed
after complete acid digestion and Ca and Mg determination by HR-CS FAAS. No statistical difference was
observed between the results obtained by both of the procedures performed.