Occurrence and Residue Pattern of Phthalate Esters in Fresh Tea Leaves and during Tea Manufacturing and Brewing

The residues of 16 phthalate esters (PAEs) in fresh tea leaves and made tea were determined via gas chromatography-tandem mass spectrometry to study their distribution and degradation characteristics during tea planting and processing. Five PAEs were detected in all fresh tea leaves, and higher concentrations were detected in mature leaves. The distribution of PAEs in fresh tea leaves ranged from 69.7 to 2244.0 μg/kg. The degradative percentages of ∑₅PAEs during green tea manufacturing ranged from 61 to 63% and were significantly influenced by the drying process. The transfer rates of PAEs-D₄ ranged from 5.2 to 100.6%. PAEs with a high water solubility showed the highest transfer coefficient in the range of 91.8-100.6%, whereas PAEs with a high log K_ow showed a low leaching efficiency below 11.9%. These results benefit the risk evaluation and establishment of a maximum residue limit for PAEs in tea.