How much fluoride is in my tea? Comparison of analytical methods and dietary exposure assessment

Tea contains the trace element fluorine in the form of fluoride, which can be beneficial or potentially harmful depending on the dose ingested, making accurate measurement in food essential. This study examined various methods for analysing fluorine in tea infusions. Combustion ion chromatography CIC and nICPMS -inductively coupled plasma mass spectrometry (detecting all fluorine containing compounds as a negative ion) provided comparable concentrations for fluorine in tea infusions. ISE results depended on the complexing agent used in the TISAB solution. An EDTA-containing buffer yielded lower fluoride concentrations than buffers containing citrate or CDTA, consistent with incomplete release of complexed fluoride under these conditions. Within the limited set of pooled samples analysed in this study, the organic tea pools contained approximately 40% less fluorine than the conventional tea pools. However, the underlying cause could not be determined from the present study design. The maximum estimated mean and P95 exposure through tea consumption for the general German population was 8% and 50% of the safe level of intake for adults aged ≥ 65 years and over (conventional tea), respectively.