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

The analytical conditions for the electrothermal atomic absorption spectrom etric determination of copper, manganese, nickel, and cobalt in different t ypes of baby foods using slurried samples are presented. Suspensions were p repared 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 dihydro genphosphate (only for copper atomization), and one drop of silicon antifoa m. The slurries were homogenized by using a potter and were introduced dire ctly into the furnace. The amount of analyte extracted to the liquid phase was investigated. The graphite furnace conditions were optimized for each e lement. 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 re liability of the procedures was checked by statistically comparing the resu lts obtained with those found by using a previous microwave-oven mineraliza tion stage and by analyzing several certified reference materials.