Interpretation of atomization mechanisms in electrothermal atomic absorption spectrometry by analysis of the absolute rates of the processes

A series of studies carried out in the author's laboratory during the period 1980-1985 and devoted to development of the theory of atomization in electrothermal atomic absorption spectrometry is summarized. The Hertz-Langmuir model of vaporization is used to interpret the Arrhenius equation and the physical meaning of its parameters, namely, the activation energy E(a) and the pre-exponential factor A. Two oxide atomization modes, equimolar and isobaric, differing in the values of E(a) and A, have been found to exist. A comparison of the calculated and experimental values of the parameters in the Arrhenius equation has permitted the mechanism of atomization in graphite furnaces to be established for compounds of 25 elements. The effect of oxygen or, alternatively, hydrogen addition to the sheath gas on the atomization of oxides is interpreted on quantitative grounds. (C) 1997 Elsevier Science B.V.