Fluorides in Tea Products and Analytical Problems with Their Determination

The problem of the occurrence of fluorides in consumed teas in terms of their biological activity and human exposure is discussed. Tea infusions are the second most widely consumed beverages after drinking water. They can be important sources of fluorides for humans. The small margin between acceptable and overdose fluoride levels in the human body requires reliable evaluation of the element's content in the large variety of available tea products. Parameters affecting the amounts of fluoride, as well as the other mineral tea components, in various teas and tea infusions are characterized. Possibilities and limitations of potentiometric ion-selective electrode and ion chromatographic methods for the determination of fluoride in tea samples are discussed. Examples of the results for fluorides obtained by the use of both techniques are given.