Rapid determination of selenium, lead and cadmium in baby food samples using electrothermal atomic absorption spectrometry and slurry atomization

Abstract

Procedures for the electrothermal atomic absorption spectrometric determination of selenium, cadmium and lead in different types of baby foods using slurried samples are described. Suspensions prepared in a medium containing 0.1% (w/v) Triton X-100, 30% (v/v) concentrated hydrogen peroxide, 1% (v/v) concentrated nitric acid and a matrix modifier (0.5% (w/v) nickel for selenium, 0.2% (w/v) nickel plus 1% (w/v) ammonium dihydrogenphosphate for cadmium and 1% (w/v) ammonium dihydrogenphosphate for lead) were introduced directly into the furnace. The graphite furnace conditions were optimized for each element. Denterium background correction was used. Calibration with aqueous standard solutions was used for selenium and lead determinations, while the standard additions method was used for cadmium determination. The 3 σ detection limits were 5.2, 3.4 and 0.4 ng g −1 for selenium, lead and cadmium, respectively. The reliability of the procedures was established by comparing the results obtained with those found for five fish-based baby foods using a previous microwave-oven mineralization stage and by analyzing six biological certified reference materials. The lead concentration was below the detection limit in all the baby foods tested.