The use of flow-injection in hydride-generation atomic-absorption spectrophotometry

Abstract

The method of analysis, where the generation of the gaseous hydrides of certain elements is used, has been thoroughly researched since its introduction in 1969. This technique is however, plagued with many interferences which necessitate cumbersome sample manipulation before accurate results are obtained. This has resulted in this technique being used only if all other options have failed. Three methods of in-line sample manipulation were studied in an attempt to change the status quo. The first method investigated was the simple in-line addition of reagents. Potassium iodide was added in this manner in order to overcome the interference resulting from the analyte being present in more than one oxidation state before generation of the hydride. Tellurium (IV) was used in the same manifold to extend the tolerance of noble metals in the determination of arsenic, selenium, and bismuth. Secondly, a small column packed with ion exchange resin was included in a new manifold which enabled the base metal interferences and certain interhydride forming element interferences to be overcome. Finally, the method of standard additions was automated in a flow-injection manifold which enabled the practice of this versatile approach without the usual sample preparation steps.