石墨炉原子吸收光谱中海水的背景吸收研究

The Study of the Background Absorption of Seawater in the Graphite Furnace Atomic Absorption Spectrometry

由于海水的成分复杂,含盐量高,给用石墨炉直接测定其中的痕量杂质带来许多困难。Sturgeon等用预先分离的方法来克服干扰。为了进行直接测定,研究海水背景吸收的来源、特点和消除方法是重要的。海水背景吸收的波长特性和在石墨管内蒸发行为的研究表明,海水的背景吸收主要来自氯化钠。时间特性的研究表明,背景吸收的时间分布及背景峰高与原子化阶段的加热方式和原子化温度有关。作者还研究了基体改进。剂和其它减小背景吸收的方法。

The Character and the source of the background absorption of seawacer and the method of decreasing the background were studied.The wavelength-dependence of the background of seawater is quite similar to that obtained from sodium chloride. The evaporation curves of seawater and sodium chloride in the graphite furnace are also quite similar. These show that nonspecific absorption of seawater arises mainly from sodium chloride. The study of atomization time vs absorbance curves shows that the outline of the background abrorptiqn is dependent on the atomization temperature and heating rate. To decrease background absorption from seawater, the addition of matrix modifiers such as nitric acid or ammonium nitrate is satisfactory.