Multi-class analysis for simultaneous determination of pesticides, mycotoxins, process-induced toxicants and packaging contaminants in tea

- 4 classes of chemical contaminants analyzed with a single method in liquid/solid tea.
- 32 chemicals simultaneously analyzed, with a broad range of properties.
- Acrylamide is included for the very first time in a multi-residue analysis.
- C18-PFP-silica palliates inefficiency of C18-silica for highly polar compounds.
- Quantification at levels as low as MRLs was achieved for most compounds.

This study attempts at uniting the analysis of four different classes of contaminants for both liquid and solid tea samples. A total of 32 compounds, classified as pesticides, mycotoxins, process-induced toxicants or packaging contaminants, were carefully chosen for their diversity of structures and physicochemical properties. The proposed method combines a sample treatment strategy coming from metabolomics with liquid chromatography analysis using a silica bonded C18-pentafluorophenyl column coupled to high resolution mass spectrometry. For tea brew, dilute and shoot method provides good quantification (70-120% recoveries and <20% RSD) for more than 80% of compounds. For tea leaves, strong matrix effects are observed, thus, matrix-matched calibration is required to reach good performances, i.e. 63% of compounds quantified and 81% detected at 10 µg/kg. Finally, method performances were evaluated against existing regulations, and it appears that 69% of contaminants are quantified and 91% detected at levels lower than their respective European regulation limits.