Occurrence Of Phthalate Esters In Tea And Migration From Plastic Packages To Tea

Phthalate esters (PAEs) are the endocrine disrupting chemicals and can lead to teratogenesis,carcinogenesis and mutagenesis. Moreover, PAEs have estrogen effects, which might cause theendocrine disorder of the male and result in the decline of sperms. On the basis of the side effects ofPAEs on human health, PAEs have been listed the priority pollutants by many countries. PAEs weredetermined in tea when the volatile compounds or aromatic components of tea were studied by thescholars from the home and abroad, but the quantitative methods were peak area nomarlization methods.What’s more, tea, especially low and medium grade tea, is always packaged in plastic bags or containers.The PAEs, existed in the plastic bags or containers, may lose from the polymeric matrix and pollute thetea. This study is to develop a modified QuEChERS sample preparation method combined with gaschromatography-tandem mass spectrometry to determine PAEs in tea and find the regular of diisobutylphthalate (DiBP) and di-(2-ethylhexyl) phthalate (DEHP) migrating from plastic packages or containersto tea. The contents and results of the study were as follows:(1). Gas chromatography-electron impact-tandem mass spectrometry (GC-EI-MS/MS) wasapplied to investigate the mass spectal fragmentation pathways of16PAEs. By studying the massspectral fragmentation pathway and fragmentation rules of PAEs, the process by which the majorfragment ions were produced was realed. These results provide a theoretical basis for selection ofquantitative and qualitative ions when GC-MS/MS technique is used to determinate PAEs in tea samples.Also, the study provides important information for the detection of PAEs and their metabolites in thecomplex matrices using the gas chromatography-tandem mass spectrometry (GC-MS/MS) technique.(2). The kinds and amounts of dispersive sorbents were optimized to modify the QuEChERSsample preparation method and the efficiencies of primary second amine (PSA), C18and graphitizedcarbon black (GCB) to purify the co-extracts were investigated and the effects of PSA, C18and GCB onthe recoveries of PAEs were also investigated in detail. The experimental results showed that PSA isable to adsorb tea polyphenols and chlorophylls, C18and GCB can make the color of the crude extractslight effectively, and GCB was found to best adsorb caffeine in the crude extracts. To take the recoveriesof PAEs into consideration, a combination of200mg PSA,100mg GCB and100mg anhydrous MgSO4was selected to purify the crude extracts. Linear range, precision and accuracy of the developed methodwere tested. Good linearity was found for all the PAEs within R2values of0.9913to0.9988when theconcentrations of PAEs were in the range of1.0,2.0,5.0,10.0,25.0μg/L to500μg/L. The recoveriesranged from85.0%to108.0%,86.5%to112.1%and84.7%to112.7%when the spiked levels were50μg/kg,200μg/kg and500μg/kg, respectively. RSDs were below20%in all cases. The accuracy andprecision of the developed method met the demands of residual analysis. The LODs and LOQs for PAEsranged from0.6μg/kg to36.0μg/kg and2.0μg/kg to120μg/kg at the signal-to-noise ratios (S/N) of3and10, respectively. A total of105tea samples were found to be contaminated with dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), DiBP and DEHP.(3). Grinded tea samples were selected to investigate the migration of DiBP and DEHP from teaplastic packages to tea samples. The grinded tea samples were stored under different temperatures (4oCand30oC), different storage time (1、7、14、21、28、35、42、49、56and63day) and differnet plasticpackages. The content of DiBP and DEHP was determined at the end of storage period. The resultsindicated that temperature affected the migration of DiBP and DEHP to some extent, the higher thetemperature, the more of DiBP and DEHP in tea samples. Different tea plastic package containeddifferent concentration of the DiBP and DEHP. The higher in plastic packages, the more in tea samples.The content of DiBP and DEHP in tea samples increased with time prolonged. Within a certain periodof time, there was a positive correlation between the concentration of DiBP and DEHP in tea samplesand storage time.