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Determination of selenium, chromium and copper in food dyes by GF AAS

The determination of selenium, chromium and copper in food dyes by graphite furnace atomic absorption spectrometry was carried out using a simple acid dissolution as sample treatment. Different chemical modifiers were investigated for the three analytes. Using the matrix-matching calibration technique, pyrolysis and atomization temperatures of 1300 and 1800 ºC, respectively, and 5 µg Pd + 3 µg Mg(NO3)2 as chemical modifier allowed the determination of Se in all the studied dyes. For chromium, 15 µg Mg(NO3)2 were used as chemical modifier, and pyrolysis and atomization temperatures were of 1500 and 2500 ºC, respectively, using external calibration. The determination of copper was carried out under the optimized temperatures of pyrolysis (1200 ºC) and atomization (2000 ºC) using 5 µg Pd + 3 µg Mg(NO3)2 as chemical modifier and, depending on the dyes, it was necessary to use external or standard addition calibration. Recoveries between 90 and 110% were obtained for the developed methods. The analysis of dyes used by food industries showed concentrations of Cu below the maximum values recommended by Brazilian legislation, however, there are no established limits for Se and Cr.

GF AAS; food dyes; selenium; chromium; copper


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