涂钼石墨管石墨炉原子吸收法测定镓、铟和铊热蒸发行为的探讨

Evaporation Behaviour in the Determination of Gallium, Indium and Thallium by Graphite Furnace Atomic Absorption Spectrometry With Molybdenum-coated Graphite Tube

本文从热力学和化学动力学的角度对消除干扰及提高吸收灵敏度的机理进行了探讨。认为在涂钼石墨管中,镓、铟和铊主要以Ga_2O、Tl_2O和InOx形式与MoO_3形成稳定的烧结物,使初始挥发温度大大提高,减少了干燥、灰化前处理过程被测物的分子挥发逸失。由于钼元素参与镓、铟和铊的原子化反应,从而改变了原子化机理,提高了原子化效率。

The mechanism of removing interference and enhancing absorption sensitivity has been studied from thermodynamic and kinetic considerations. Gallium, indium and thallium in Mo-coated graphite tube form mainly stable sintered materical in the form of Ga_2O, T1_2O and InO_X, with MoO_3 to enhance greatly initial volatilization temperature and decrease process that molecular species escaped before drying and ashing. Because molybdenum participated in atomization reaction of gallium, indium and thallium, it can change atomization mechanism and improve atomization efficiency.