Analysis by solid sampling graphite furnace atomic absorption spectrometry: Success with some difficult samples

It is shown that direct solid sampling graphite furnace atomic absorption s pectrometry (SS-GFAAS), equipped with a transversely heated graphite atomiz er and an efficient deuterium background correction can be a powerful alter native for the trace analysis of heavy metals in different materials. The d irect solid sampling technique has been successfully applied to the analysi s of cements (Cd, Pb and Cr), calcium fluoride single crystals (Cd and Pb), barytes (Cd, Pb and Cu) and deposits of the surface of historical building s (Pb, Cr and Mn) using the platform technique in a very wide concentration range (upper-ppm to sub-ppb range). The analytical results from the SS-GFA AS were compared with those obtained by Zeeman-GFAAS or FAAS after microwav e aqua regia extraction and/or aqua regia-hydrofluoric acid digestion. In m any cases good agreement was achieved with values obtained by reference met hods. When using test sample masses between 0.029 to 0.756 mg an overall pr ecision of about 10% RSD was obtained after standard calibration using diff erent masses of certified reference materials (CRMs) such as sediments and soils. Difficulties which can arise in special cases - like calibration pro blems, relatively bad precision, poor agreement with reference methods - ar e shown and discussed.