Comparison of chemical modifiers for direct determination of Cd, Cu and Zn in food stuffs by solid-sampling-ETAAS

In this work, the capability of different chemical modifiers (Pd, Pd/Mg(NO3)2, Pd/NH4NO3, NH4H2PO4, NH4H2PO4/Mg(NO3)2) to eliminate the matrix effects in the direct determination of Cd, Cu and Zn in food-stuffs by solid sampling-electrothermal atomic absorption spectrometry was compared. The alternative analytical lines were used for determination of Cu (327.4 nm) and Zn (307.6 nm) in order to allow the introduction of reasonably high sample mass into the furnace. Mixed modifiers containing palladium were useful to eliminate the matrix effect in Cd determination. For Cu and Zn determination the application of Pd shows satisfactory analytical performance. In the determinations of Cd and Zn the phosphate containing modifiers shows elimination of matrix effects only when applying them to a partially pyrolysed sample (at 400 °C). The achievable limits of detection for Cd, Cu and Zn in solid samples were 0.279 ng g−1; 0.020 μg g−1 and 2.04 μg g−1, respectively.