Abstract: 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.

Key words: Atomic absorption spectrometry, Graphite furnace, Background absorption, Seawater