Determination of barium using graphite furnace atomic absorption spectrometry

Abstract

The determination of Ba in a graphite furnace is less routine than the determination of most other elements. At the primary Ba resonance line, high levels of continuum emission from the heated graphite tube and from the sample matrix result in an increase in noise in the analytical signal.

We have improved the atomisation efficiency of Ba by treating pyrolytic graphite coated graphite tubes with thorium. Attempts to use a Pd-Mg(NO₃)₂ matrix modifier were unsuccessful. Using an atomisation temperature of 2550 °C, a characteristic mass of 7.0 pg per 0.0044 A s and a detection limit of approximately 25 pg or about 2.5 µg l^–1 in a 10-µl aliquot were obtained.