Elemental analysis of teas, herbs and their infusions by means of total reflection X-ray fluorescence

This work shows that total reflection X-ray fluorescence (TXRF) is a suitable tool for multi-elemental analysis of teas, herbs and their infusion. A low power benchtop TXRF spectrometer was used. Safety of infusion consumption was evaluated. Many commercially available teas,herbs and roots samples were analyzed. Total concentrations of thirteen elements K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr, Ba and Pb as well as their extraction efficiencies into infusion were determined. The content of Pb is highlighted in all teas and herbs, in the concentration range between 0.5 and 4.8 mg/g, but only in infusions of herbs. Chemometry was applied for classification purposes. Elemental daily intakes with respect to infusion drinking was calculated and compared with dietary reference intake values. Results show that TXRF is a fast and simple technique for safety check of tea and herb infusions on a routine basis.