Atomic absorption spectrometric determination of trace elements in lithium fluoride crystals

A new analytical method for cationic impurities in LiF using atomic absorption spectrometry is presented. The method consists in dissolving in HClO4 followed by a suitable dilution which replaces the toxic and corrosive for glass labware dissolving in HF. The number of elements which can be analysed by AAS is increased because the HClO4 compounds are much more soluble than fluorides. Thus the method sensibility is increased by about ten times and samples contamination with additional impurities due to HF excess is avoided. Simultaneously the analysis time is much reduced. Taking into account the possibility of explosions in certain conditions some cautions concerning the use of HClO4 are necessary. The method is suitable for analysis of Ca, Mg, Na, Cu, Fe, Ni and Pb in the ppm range with a 95% margin of confidence. (author)