Determination of lead by atomic absorption spectrometry using tube-in-flame atomisation and solid sampling

Abstract

The use of a graphite tube introduced into an air-acetylene flame for the determination of Pb in solid samples is described. A slurry of NIST SRM 2704 Buffalo River Sediment was prepared and immediately filtered to collect the solid material on a cellulose filter. Small pieces, ≈3.2 mm diameter, of the filter-paper containing the solid material were placed, by means of a thin stainless-steel spatula, inside a graphite tube. This was then introduced into the flame for atomisation and atomic absorption determination of the Pb content of the SRM. Small pieces of the NIST SRM 3087a Metals on Filter Media were also analysed for Pb in a similar fashion. The Pb concentration values determined for the Buffalo River Sediment SRM were 160±20 μg g ^–1 (certified value 161±17 μg g ^–1 ), whereas those for the Metals on Filter Media SRM were 41.54±3.55 μg per filter (certified value 40.38±0.92 μg per filter), confirming the accuracy of the results obtained. The standard deviations for the above measurements performed on the solid samples were, as expected, highly dependent on the homogeneity of the distribution of the analyte in the SRMs and on the uniformity of the layer of solid sample deposited on the filter-papers.