MICRODETERMINATION OF FLUORINE IN ORGANIC COMPOUNDS BY POTENTIOMETRIC TITRATION USING A FLUORIDE ELECTRODE

A method suitable for rapid and routine determination of organically bound fluorine is described using, as the titrant, a 0.005M solution of thorium nitrate in 80 volume per cent ethanol. A fluoride electrode is the end point detector. The titration medium is adjusted to 0.01M in nitric acid and 80% by volume in alcohol. The sample is decomposed by combustion in a polycarbonate oxygen flask using dodecyl alcohol as a combustion accelerator. Results of determination on typical microchemical fluorine standards in the sample range of 1 to 10 mg are within the ±0.3% (absolute) values traditional for microelemental analysis. Phosphorus and sulfur, if present, may interfere, and prior separation is suggested. © 1969, American Chemical Society. All rights reserved.