Determination of aluminium and chromium in slurried baby food samples by electrothermal atomic absorption spectrometry

Electrothermal atomic absorption spectrometry was used to determine alumini um and chromium in different types of baby foods. Samples without previous treatment were introduced into the atomizer as suspensions, which were prep ared in a medium containing 0.1 % (w/v) Triton X-100 (for chromium) or 10% (v/v) ethanol (for aluminium), 5% (v/v) concentrated hydrogen peroxide, and 0.5% (v/v) concentrated nitric acid. The slurries were homogenized with a potter and introduced directly into the furnace. The presence of nitric aci d allowed a substantial amount of analyte to be extracted to the liquid pha se. No matrix effect was observed and aqueous standard solutions were used for calibration. The detection limits were 4 and 50 pg for chromium and alu minium, respectively; characteristic masses were 3.8 pg for chromium and 18 pg for aluminium. Reliability of the procedures was checked by statistical ly comparing the results with those obtained with a previous microwave oven mineralization stage and by analyis of several certified reference materia ls. Values for the aluminium content ranged between 0.4 and 3.0 mug/g, and for chromium between 0.003 and 0.06 mug/g.