DETERMINATION OF TRACE AMOUNTS OF SELENIUM IN NI-BASE HEAT-RESISTING ALLOYS BY GRAPHITE-FURNACE ATOMIC-ABSORPTION SPECTROMETRY

Graphite furnace atomic absorption spectrometry (GF-AAS) using direct atomization of the acidic sample solution was studied to establish a rapid and sensitive determination procedure of trace selenium in nickel-base heat-resisting alloys. The interferences of matrix and co-existing elements were minimized by using the stabilized temperature platform furnace (STPF) method in combination with alternating current Zeeman background correction, and thereby the sensitivity of GF-AAS in selenium determination was significantly improved. The detection limit (3 sigma of blank value) was 23.5 pg, which corresponded to 0.12 ppm selenium when the weight of sample was 0.5 g. The proposed procedure can be applied to the determination of selenium in nickel-base alloys without pretreatment of the sample solution and also calibration with solid standard samples or by standard additions.