Determination of fluoride with the ISE and standard addition

Fluoride is a very important species, both from an economic and a strategic viewpoint. It plays an essential role in the production of steel, glass, ceramics and cement and is also an important ion for medicine, dentistry and the food industry.

An easy and fast method for determining fluoride ions in solution is standard addition with the Fluoride Ion Selective Electrode from Metrohm. While dissolved fluoride can be measured directly, fluoride bound in cement or minerals, such as fluorspar, requires very specific sample preparation. The linked Application Bulletin (Number 82) provides a wide spectrum of sample preparation techniques for both dissolved and solid samples.

The advantage of standard addition is that no calibration of the electrode is required meaning that no dilution series needs to be prepared prior to the measurement, which occurs directly in the sample solution. A further advantage is that the analysis can be performed with Metrohm's 781 pH/Ion Meter, an instrument that is very affordable. Titrando titrators provide this method as well, whether controlled by tiamo 1.2 or by PC/Touch Control 4.1 software.