A highly specific and high extraction-rate method for the analysis of dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), diisobutyl phthalate (DiBP), and di-(2-ethyl) hexyl phthalate (DEHP) in tea samples was developed. Based on three-factor Box–Behnken response surface design, solid-phase extraction (SPE) of five phthalate ester (PAE) residues in tea was optimized. Optimal extraction conditions were found for extraction temperature (40 °C), extraction time (12 h), and ratio of tea to n-hexane (1:20). The dynamic distribution of PAEs at each stage of black tea processing was also analyzed, and it was found that the baking process was the main stage of PAE emission, indicating that traditional processing of black tea significantly degrades PAEs. Further, principal component analysis of the physicochemical properties and processing factors of the five PAEs identified the main processing stages affecting the release of PAEs, and it was found that the degradation of PAEs during black tea processing is also related to its own physicochemical properties, especially the octanol–water partition coefficient. These results can provide important references for the detection, determination of processing losses, and control of maximum residue limits (MRLs) of PAEs to ensure the quality and safety of black tea.

Plasticizers, i.e., phthalate esters (PAEs) were liable to be detected from fresh tea leaves and tea products. In order to monitor the pollution of PAEs in tea plants and compare the difference among PAEs content of tea cultivars, fifteen elite cultivars in tea plant cultivar gardens were chosen. PAEs were extracted from the upper mature leaves and lower mature leaves of tea bushes and determined via GC–MS once every two months, six times in total in one anniversary. DMP, DEP, DiBP, DBP, and DEHP were detected in fifteen tea cultivars. DBP was the predominant congener in fifteen tea cultivars, which was followed by DiBP. PAEs content in upper mature leaves was significantly lower than that in lower mature leaves in all months. There was no significant difference among PAEs content from the fifteen tea cultivars. Except for summer, the PAEs content of fresh tea leaves gradually increased from spring to winter. The correlation analysis result was that PAEs had significant negative correlation with air temperature and positive correlation with air quality index (p < 0.01). The mutual correlation among the five PAEs were significant (p < 0.05). According to cluster analysis, three types of fresh tea leaves with high, medium, and low accumulation accounted for 26.7%, 20%, and 53.3%, respectively. The results could supply a reference for monitoring of pollution of PAEs in fresh tea leaves, as well as an evaluation of PAEs content difference of tea plant cultivars.