Design and optimisation of a flow injection hydride generator and its use for automated standard additions

Abstract

A continuous flow approach to the generation of the gaseous covalent hydrides for the determination of certain Group IV, V and VI elements is described. A flow injection hydride generator in which the sample is injected into an acidic carrier stream, which is subsequently merged with the reductant, has been developed. This apparatus allows rapid analysis, ease of automation and simple in-line handling of interferences. The tried and tested method of standard additions is automated and simplified in the described apparatus. The determination of bismuth in the presence of palladium is used to demonstrate the feasibility of the flow injection approach to standard additions. The apparatus has also been optimised for the determination of antimony, arsenic, bismuth, selenium and tellurium yielding detection limits of 10, 8, 2, 6 and 3 ng ml^–1, respectively. Germanium, lead and tin are also measurable using the apparatus, however, the detection limits achieved were similar to those obtainable by flame atomic absorption spectrometry.