The effect of thermal sample pretreatment on the absorption signal in graphite furnace AAS.

The origin of the unusual maxima observed in the decomposition curves for pure solutions of some elements has been investigated theoretically and experimentally. An increase in the atom residence time caused by longitudinal redistribution of the analyte in the tube during the pyrolysis step was found to be responsible. The effect can be observed only if the sample is atomized under gas-flow conditions. To prevent any influence on analytical results, atomization should be done in the gas-stop mode.