Photometric titration of fluoride with zirconyl chloride using the brinkmann probe absorptiometer
Abstract
Fluoride masses in the range 0.15–25 mg in a total volume of 30 cm3 were titrated photometrically at 520 nm using zirconyl chloride as titrant and sodium alizarin-3-sulphonate as indicator. The instrument used was the highly suitable Brinkmann fibre-optic probe absorptiometer. The influence of pH and other variables was assessed. The coefficient of variation for medium and high fluoride concentrations in the range covered was 0.18%. Phosphate, aluminium and iron(III) interfere badly. Comparison was made with the lanthanum nitrate potentiometric titration.