Determination of essential and non-essential elements in various tea leaves and tea infusions consumed in Turkey

Abstract

Tea is one of the most popular beverages in the world. Thus, the chemical components in tea are of great interest, especially in relation to health. In this study, 12 tea samples (10 black, 1 white and 1 green) and 5 herbal tea samples were purchased from supermarkets in Izmir, Turkey. Sample preparation has been performed using wet and microwave digestion procedures. The elemental content (Fe, Zn, Cu, Mn, Ni, Na and K) in the digests and infusions has been analysed. Generally, elemental contents in tea leaves were found to be higher than those in tea infusions. The accuracy of the method was checked and confirmed by standard reference material analyses. The comparison of wet and microwave digestion has not shown significantly different results. Therefore, the microwave digestion procedure was preferred because it is less laborious. The elemental intake related to tea consumption has also been studied.

Keywords:

• tea leaves
• tea infusions
• black tea
• green tea
• elements
• microwave digestion
• flame atomic absorption spectrometry

Acknowledgements

The authors would like to thank the Scientific and Technical Research Council of Turkey (TUBITAK) for financial support.