Direct analysis of solid samples by graphite furnace atomic absorption spectrometry with a transversely heated graphite atomizer and D-2-background correction system (SS GF-AAS)

An instrumental design for the analysis of heavy metals in solid samples (certified reference materials, river sediments, cements) by direct graphite furnace atomic absorption spectroscopy (SS GF-AAS) is presented and outlined. A high performance atomic absorption spectrometer with a D-2-background corrector and a transversely heated graphite atomizer was modified. Solid sampling was achieved by a mechanical module combined with an ultra microbalance. Cadmium, lead and chromium in different samples (sample weights between 20-400 mu g) have been determined in the mu g/g- to ng/g-range with the graphite-platform technique. Different ways of calibration and inhomogeneity problems are discussed. The precision of SS GF-AAS is equal to the precision of the conventional AAS-technique with chemical digestion (microwave digestion system, Zeeman-AAS). It is shown that SS GF-AAS is a reasonable alternative to the conventional technique for selected analytical problems.