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A. Hioki, and M. Kubota
[Bunseki Kagaku., Vol.43, pp.355-360, 1994]
The accuracy of PbClF gravimetry for the determination of fluoride ions was studied. An indirect complexometric determination of fluoride ions was carried out based on the precipitation of PbClF and determinations of both the lead(II) concentration of a PbCl2 solution used and that of the filtrate. Gravimetry and indirect complexometry were simultaneously carried out for each single aliquot of a fluoride solution. For correcting both the gravimetry and complexometry results, the concentration of fluoride ions left in the filtrate was determined by a fluoride-ion selective electrode method. The purity of sodium fluoride based on gravimetry (99.94±0.05%, 4 determinations) was in good agreement with that based on indirect complexometry (99.93±0.03%,8 determinations). Moreover, the content of chloride ions in the precipitation of PbClF was determined by the AgCl gravimetry.