ELECTROTHERMAL AAS DETERMINATION OF BISMUTH, ANTIMONY AND TIN IN HIGH-PURITY WO3

Four methods for the bulk trace determination of Bi, Sb and Sn in WO3 were developed and tested. In all cases, the final determination is carried out by graphite furnace atomic absorption spectrophotometry. The limits of detection range from 1-mu-g/g for a very fast and simple method to 50 ng/g for a method comprising a trace-matrix separation by sorption and complexation on activated carbon powder loaded with TMDTC. A way of preparation of standard reference WO3-samples doped with varying amounts of Bi, Sb and Sn traces is also described.