The
tea shrub is grown in long-standing orchards, an environment
that is suitable for persistent weed growth, which is increasingly
controlled by herbicides. Therefore, there is increasing concern that
tea consumers may be exposed to herbicide residues. In this study,
the levels of glufosinate-ammonium (GLU), glyphosate [N-(phosphonomethyl) glycine; PMG], and its metabolite aminomethyl
phosphoric acid (AMPA) were determined in tea samples by HPLC–MS/MS
using several current purification methods and a new method that we
developed herein. The matrix effect of our proposed method was between
-27.3 and 27.7%, which was lower than that in other methods, indicating
that this method effectively reduced the interference of tea matrix
in the mass spectrometry process. This method was used to determine
the levels of PMG, GLU, and AMPA in 780 samples, including six traditional
Chinese teas (green tea, black tea, oolong tea, dark tea, white tea,
and yellow tea) and a floral tea, from 14 provinces of China. Probability
estimates showed that the 95th percentile risk entropy
values of the three pesticide residues were far below the acceptable
risk level. The risk assessment results showed that exposure to PMG,
GLU, and AMPA caused by drinking tea beverages poses no significant
risk to human health.