ABSTRACT
Fluorides can exist as gases, liquids, and solids. The most commonly used fluoride is hydrogen fluoride (HF). All of the methods described as gas and vapor fluoride analyzers will detect this compound. Many solid fluorides are soluble in water and form the fluoride ion. In most cases, the quantitative amount of fluoride in a sample is required. However, in other cases only knowledge of the qualitative presence of HF is required. Other liquid and gaseous fluorides are much more stable and do not easily form HF. In the case of ion-specific electrodes, titration, and colorimetric methods, fluoride analysis is actually performed on an aqueous sample. The fluoride-selective ion electrode, in conjunction with a reference electrode, develops its potential across a doped fluoride crystal membrane. The two most common methods of analyzing organic fluorides, such as Freons, are gas chromatography or pyrolysis followed by any of the conventional analysis procedures.
