Background Corrections in the Determination of Cd and Pb by Flame AAS in Plant and Soil Samples with High Fe Levels

Abstract

Plant leaf digests and soil extracts were analyzed for Cd and Pb by flame AAS in three ways: with deuterium background correction, with the Smith-Hieftje background correction system, and without any background correction. Background correction proved to be necessary for both elements and for both types of material. The two background correction systems gave equal results, provided that Fe concentrations were low. High Fe concentrations caused spectral interference (i.e., structured background), which was overcompensated by the deuterium system. The Smith-Hieftje system, however, produced correct results.