Determination of lead and bismuth in nickel-base alloys by graphite furnace atomic absorption spectrometry using continuum source background correction

Abstract

The analysis of trace lead and bismuth in nickel-base alloys using the stabilized temperature platform furnace atomic absorption spectrometry (AAS) with deuterium background correction was investigated. The peak times of lead and bismuth were different in different matrices. Lead was determined directly without any chemical modifier since the background absorption caused by the alloy matrix was compensated by the continuum background corrector. Aqueous standards were used to construct the calibration curves. The high background absorption encountered in the determination of bismuth could not be eliminated by chemical modifiers, neither palladium nor ethylenediaminetetraacetic acid (EDTA). Background absorption was effectively reduced when trace bismuth was separated from the major matrix by coprecipitation with the addition of ammonium before determination by AAS. Hence, subnanogram levels of lead and bismuth in the aqueous solutions of nickel-base alloys were determined precisely with the optimum instrumental conditions established in this work. The accuracy and precision of the proposed methods were evaluated through the analysis of standard reference materials of nickel-base alloys. The experimental results agreed closely with the certified values and the reference values.