The determination of antimony in lead–antimony alloys using ICP-OES and internal standardisation

Abstract

Lead–antimony alloys are used in certain applications where ductile alloys are required. The physical properties of the alloy will depend primarily on the chemical composition, in this case, the amount of antimony present. Antimony will inhibit corrosion, change the density, and also increase the hardness of the alloy. An analytical test procedure making use of an inductively coupled plasma optical emission spectrometer (ICP-OES) was needed for the accurate and precise determination of the antimony content of lead–antimony alloys. The sample for analysis was prepared with an internal standard and quantified using an ICP-OES. Cadmium was selected as internal standard because it emits at a wavelength close to antimony and it has a first ionisation potential almost the same as antimony. Three certified reference materials were analysed. The results obtained for three reference materials were precise and accurate. Day-to-day repeatability was better than 1.4% m/m. Within-day repeatability of an alloy was 0.016% m/m.