Composition, distribution and risk of total fluorine, extractable organofluorine and perfluorinated compounds in Chinese teas

- Inorganic fluorine was the main form of tea fluorine, and most EOF in tea were still unknown.
- PFCs residues in tea were mainly short-chain, and PFOA could be an indicator chemical for tea PFCs.
- Less fermented teas contained significantly higher PFCs than more fermented teas (p < 0.01).
- The highest TF content found in tea samples poses risk of fluorosis.
- PFCs residues in tea samples caused no immediate harm.

To explore the residual characteristics of fluorine and perfluorinated compounds (PFCs) in tea, the total fluorine (TF), extractable organofluorine (EOF) and PFCs in 19 Chinese commercial teas of five categories were measured using cyclic neutron activation analysis combined with HPLC-MS/MS. The results showed that fluorine mainly existed as inorganic fluorine in teas, and identified fluorine (∑PFCs quantified as F) only accounted for 0.023-0.41% of EOF, indicating that most EOF in tea were still unknown. 50-99% of ∑PFCs in tea were short-chain (C ⩽ 6), while perfluorooctanoic acid was the typical PFCs residual species. Less fermented teas contained significantly higher PFCs (mean, 20 ng/g) than more fermented teas (3.0 ng/g, p < 0.01), suggesting that microbe may degrade PFCs during fermentation. The highest TF content was discovered in Hubei brick tea, which poses risk of fluorosis, whereas PFCs residues in teas caused no immediate harm.