Characterization of a pressurizable two-step atomizer for atomic absorption spectrometry

A two-step atomizer consisting of a transversely heated atomization tube wi th integrated contacts and a cup furnace for sample vaporization was constr ucted. The system could accommodate tubes of various lengths and it could b e operated at selected pressures. There was no physical contact between the tube and the cup and mainly diffusion was responsible for the sample vapou r transport from the cup to the tube. Under these conditions there was an u navoidable loss by 40% of the peak area signals due to the gap between the cup and the tube. For a 24-mm tube, characteristic masses were on the avera ge three times lower than for the state of the art transverse heated graphi te atomizers (THGA). By de-coupling the processes of analyte vaporization a nd atomization the dynamic working range could be increased by three to six times using conventional measurements by atomic absorption spectrometry (A AS). In this case the cup temperature and hence the rate of analyte transpo rt from the cup to the tube was controlled such that atom density in the tu be did not exceed the linear range of the absorbance measurement. Carrying out clean-out steps at reduced pressure decreased memory effects. (C) 2000 Elsevier Science B.V. All rights reserved.