Use of Some Transition Metal Cations in Potentiometric and Spectrophotometric Microdetermination of Fluoride and Evaluation of Uptake Rate by Tooth Enamal

Abstract

In this work silver amalgam electrode was utilized for potentiometric microdetermination of fluoride (50–1500 ppm) and its uptake rate (6.5 to 14.9 mg.) by tooth enamel powder (1 gm) under various conditions. The determination depends upon the mercurimetric titration of excess EDTA added to excess of metal cations as Fe (III), Th (IV) and Sm (III) that remained after interaction with fluoride sample. This work was successfully applied in spectrophotometric microdetermination of fluoride (13–380 ppm) and its uptake by tooth enamel powder (25.5 to 179 mg/1gm) via fading of colour of Fe (III)–thiocyanate and Fe (III)-salicylate complexes. This work proved that the fluoride used in tooth remedy is mostly chemically bonded to the tooth construction but that physically absorbed was washed with water. It was observed that as the concentration of fluoride and the time of contact with tooth enamel were increased the fluride uptake rate by the enamel powder increased.