电热原子化机理研究——Ⅰ.测定原子化过程活化能的新方法

STUDIES ON THE MECHANISM OF ELECTROTHERMAL ATOMIZATION——Ⅰ.Anew method for the determination of activation energy

本文提出了用正态分布函数模拟时间-信号轮廓;建立了测定原子化过程动力学参数的模型。此法有效地消除了由Sturgeon法、AKMAN法所得的Arrehenius曲线的非线性,为原子化过程动力学参数的准确测定打下了基础。并结合热力学方法,对镍、银、砷、铋的原子化机理进行了探讨。

In this paper, it has been proposed that the transient atomic absorption signal generated during atomization process can be simulated by a normal distribution function, therefore, a new method for the determination of kinetic parameters was developed in the electrothermal atomic absorption spectrometry.The Arrehenius plot obtained with this method is linear over a wide temperature range. By using a com- bined thermodynamic and kinetic approach, the atomization mechanisms for nickel, silver, arsenic and bismuth have been studied. It was showed that rate-determining process of these elements is as follows: the vaporization of metal for nickel and silver, the dissociation of AsO (g) for arsenic and the dissociation of dimes Bi_2(g) for bismuth.