Determination of copper, cobalt, nickel, and manganese in baby food slurries using electrothermal atomic absorption spectrometry

The analytical conditions for the electrothermal atomic absorption spectrometric determination of copper, manganese, nickel, and cobalt in different types of baby foods using slurried samples are presented. Suspensions were prepared in a medium containing 0.1% w/v Triton X-100, 30% v/v concentrated hydrogen peroxide, 1% v/v concentrated nitric acid, 1% w/v ammonium dihydrogenphosphate (only for copper atomization), and one drop of silicon antifoam. The slurries were homogenized by using a potter and were introduced directly into the furnace. The amount of analyte extracted to the liquid phase was investigated. The graphite furnace conditions were optimized for each element. No matrix effect was observed, and calibration could be carried out using aqueous standard solutions. The detection limits were 3.4, 2.1, 5.4, and 3.7 pg for copper, manganese, nickel, and cobalt, respectively. The reliability of the procedures was checked by statistically comparing the results obtained with those found by using a previous microwave-oven mineralization stage and by analyzing several certified reference materials.