A High Speed Method of Continuous Background Correction in Atomic Absorption Spectrometry

Abstract

The need for background correction in atomic absorption spectrometry (AAS), particularly when graphite furnaces are used to generate the atomic vapor, is discussed. It is shown that a Beckman hydrogen arc lamp is suitable as a continuum source from the point of view of noise, extent of its useful broad band absorption, and light intensity for background-corrected absorption (BCA) measurements over the wavelength range examined (200 to 460 nm). The standard method of determining tin present in rock samples as cassiterite, by extraction as the volatile tin iodide, was examined by flameless AAS with BCA. The method corrects for the large nonatomic absorption present, it is rapid, and it enables easier examination of solutions containing low concentrations of tin (detection limit for a 1 g starting sample is ∼1 jug tin).