Elemental analysis of teas and their infusions by spectrometric methods

A non-alcoholic beverage, tea made from leaves of the Camellia sinensis plant is a potentially rich source of dietary important elements and is consumed by nearly half the world's population. Of the types of tea, black, oolong and green teas are the most popular, so knowledge about their elemental characteristics is especially important. Habitual drinking of tea infusions may significantly contribute to daily dietary requirements of elements or lead to accumulation of elements and intoxication under overdose conditions. It is especially important that toxic and/or heavy metals, which may be retained by tea plants to a great degree, can have adverse effects on human well-being and health. Accordingly, accurate, precise determination of the mineral content of tea leaves from which tea is made, teas available commercially and their infusions allows us to assess exposure to non-essential elements and to judge the nutritional value of tea reliably. Different instrumental techniques are used for elemental analysis, but atomic and mass spectrometries are preferred most. This review surveys the elemental analysis of teas and their infusions, and the consequences of the presence of various elements in this beverage. We also consider sample-preparation procedures before analysis, the results of analysis and the manner of controlling and assuring the quality of those results. (C) 2012 Elsevier Ltd. All rights reserved.