Use of a furnace with a graphite filter for electrothermal atomic absorption spectrometry

Abstract

The development of an atomization technique for electrothermal atomic absorption spectrometric (ETAAS) analysis, based on the filtration of the analyte vapour through heated graphite, is presented in its historical context. Initially the method was applied to the analysis of solids. Despite the effectiveness of atomization, the time taken to prepare each solid sample and graphite tube arrangement made single-element determinations impractical using the ETAAS technique. The proposed new version of the furnace with a graphite filter was designed for the analysis of liquids using commercial ETAAS instruments equipped with an autosampler, programmable power supply and a system for background correction. The main advantages of the atomizer were discovered in the course of the determination of Al, Bi, Cd and Cu for different sample volumes, and Cd, Pb and Bi in the presence of NaCl and CuCl₂ matrices. These advantage include: a 1.6–2.8-fold increase in sensitivity; the possibility of increasing the volume of doped solutions up to 100 µl, and at the same time reducing the drying period to 15 s; and obtainment of a lower level of spectral background and chemical interferences without chemical modification. The accuracy of the method was verified by the determination of Cd and Pb in whole blood and steel.