Continuous Hydride Generation System for the Determination of Trace Amounts of Bismuth in Metallurgical Materials by Atomic Absorption Spectrometry Using an On-line Stripping-type Generator/Gas–Liquid Separator

Abstract

A method for the determination of trace amounts of bismuth using flow injection and atomic absorption spectrometry with hydride generation was developed. The introduction of 50 µl of sample and tetrahydroborate solution into the HCl and aqueous carriers in a merging zones manifold allows the formation of bismuthine, which is separated from the liquid phase in an on-line stripping-type generator/gas–liquid separator. The calibration graph is linear from 0.1 to 100 ng ml ^-1 Bi with a detection limit (3 σ ) of 320 pg ml ^-1 Bi (corresponding to 16 pg Bi). The relative standard deviation for 20 replicates varies from 10% for 0.1 ng ml ^-1 Bi to 1.9% for 100 ng ml ^-1 Bi, with an injection frequency of up to 150 samples h ^-1 . Ni ^II , Co ^II , Ag ^I , Hg ^II , Se ^IV and Sb ^III interfere, but they can be masked with a thiourea–KI solution. The applicability of the proposed method to metallurgical samples was demonstrated by the analysis of certified reference materials.