Determination of bismuth and lead in steel and cast iron by hydride generation and zeeman atomic absorption spectrometry

Procedures are described for the determination of lead and bismuth in steel and cast iron by atomic absorption spectrometry (a.a.s.). Two alternative decomposition procedures are applied, namely, sodium peroxide fusion in zirconium crucibles and digestion with a nitric—perchloric acid mixture in a Bethge digestion apparatus. The latter technique is preferred. Lead is measured by electrothermal a.a.s. with Zeeman background correction. Bismuth is determined after hydride generation with sodium tetrahydroborate. Calibration is done by standard addition. The sensitivities obtained are 1 μg g−1 for lead in steel and cast iron and 5 μg g−1 for bismuth in white and grey cast iron. The r.s.d, is generally better than 10% for > 10 μg g−1. The method is applied to standard reference steel samples and several specimen cast irons.