Multi-element atomic-absorption analyses with a gas-stabilised arc as primary light source

Abstract

The use of a gas and wall-stabilised arc as primary light source for multi-element atomic-absorption measurements was investigated. A solution containing the elements of interest was injected, in aerosol form, into the arc, and the resonance lines excited. The concentration of the solution sprayed into the arc was the only source parameter appreciably influencing the sensitivity (i.e., the degree of atomic absorption by the flame). It was found for fourteen arbitrarily chosen elements that the sensitivity was equal to two thirds of the sensitivity obtained with hollow-cathode lamps as primary sources. The reproducibility of measurement, when non-absorbing reference lines were used, was similar to that obtained with hollow-cathode lamps. The intensity of the background emission of the arc was so low in comparison with the line intensities that it had little effect on the sensitivity. With this source, the atomic-absorption working range can be extended by the variation of the solution concentration in the arc, and this proved useful when lead and zinc were determined simultaneously in a brass sample.