Rapid digestion procedure for the determination of lead in vegetable tissues by electrothermal atomisation atomic absorption spectrometry

Abstract

A rapid digestion procedure is described for the determination of lead in vegetables. Vegetable tissues were digested to clear solutions using a simple three-step procedure in an open beaker using a mixture of nitric and perchloric acids. All carbonaceous matter and silicates were decomposed. Lead was determined quantitatively by graphite furnace atomic absorption spectrometry using a direct method in the presence of 1%m/V(NH4)2HPO4 as matrix modifier. The application of the method to reference materials (tomato and citrus leaves) gave results in agreement with values given by the National Institute of Standards and Technology: 6.3 ± 0.3 µg g–1 for Standard Reference Material (SRM) 1573 Tomato Leaves and 13.3 ± 2.4 µg g–1 for SRM 1572 Citrus Leaves. Recoveries of lead from vegetable samples ranged between 100 and 101%. The relative standard deviation was less than 4%.