探针恒温原子化机理的研究

STUDIES ON THE PROBE ISOTHERMAL ATOMIZATION MECHANISM

本文应用热力学和动力学相结合的方法,研究了石墨炉原子吸收分析中,探针恒温原子化的原子形成机理。在将原子的形成考虑为零级动力学过程的基础上,提出了一种新的计算原子形成速率常数的公式。应用Arrhenius定律,计算了探针原子化测定Cd、Pb、Sb、In和Cu的原子形成活化能。结果表明,Cd、Pb和Sb的活化能与它们的金属气化热一致,Cu和In的活化能与它们的双原子分子的键能一致。

The mechanism of atom formation of analyte is studied in graphite furnace atomic absorption spectrometry for probe isothermal atomization by means of a method that combines thermodynamics and kinatics. A home-made fully automatic probe system is employed for all the experiments. A new calculated formula of atom formation rate constant is proposed, in which the process of atom formation is considered as a zero order reaction. The atom formation activation energy of Cd, Pb, Sb, In, and Cu is calculated by using Arrhenius law, and the results are in agreement with the latent heat of vaporization of the metal for Cd, Pb, and Sb and the bond energy of the double atoms for In and Cu.