18份市售牛奶中全氟化合物及其前体物质含量分析

Analysis of perfluoroalkyl substances and their precursors in eighteen market milk

目的分析我国18份市售牛奶中全氟化合物及其前体物质的污染状况。方法牛奶样品来自宁夏、内蒙、北京、天津、河北、山西、重庆和广东等8个省份，共18份牛奶样品。应用超高效液相色谱一串联质谱法和同位素稀释技术对牛奶样品中8种全氟化合物和11种全氟化合物前体物质含量水平进行分析，进行膳食暴露评估。结果牛奶样品中检出全氟辛酸（PFOAl、全氟十一酸（PFUdA）和全氟辛烷磺酸（PFOS）等3种全氟化合物，检出样品数分别为5、12、14份，含量范围分别为〈检出限（LOD）～431．94pg／ml、〈LOD～15．95pg／ml和〈LOD～126．98pg/ml。牛奶样品中检测出3种全氟化合物前体物质，分别为1H，1H，2H，2H-全氟己基磺酸（4：2 FTS）、1H，1H，2H，2H-全氟辛基磺酸（6：2 FTS）和1H，1H，2H，2H．全氟辛基-2-磷酸盐（6：2 diPAP）。仅在1份样品中检出4：2FTS，含量为3．75pg／ml；检出6：2 FTS与6：2 diPAP的样品数分别为12份与3份，含量范围分别为〈LOD～2．49和〈LOD～24．56pg／ml。牛奶中PFOA和PFOS膳食摄入量范围分别是2．49×10^-3～405．89×10^-3和36．10×10^-3～119．32×10^-3ng·kg^-1·d^-1。结论18份市售牛奶中具有不同程度的全氟化合物及其前体物质污染物残留；本研究牛奶样品中的全氟化合物每日摄入量远低于欧盟设立的健康阈值（PFOS：150ng·kg^-1·d^-1，PFOA：1500ng·kg^-1·d^-1）。

Objective To explore the level of perfluoroalkyl substances （PFASs） and their precursors in 18 market milk samples of China. Method The 18 milk samples were selected in 8 provinces of China, including Ningxia, Neimeng, Beijing, Tianjin, Hebei, Shanxi, Chongqing, and Guangdong. 8 PFASs and 11 PFAS precursors were measured by ultra-high performance liquid chromatography-tandem quadruple mass spectrometry （UPLC-MS/MS）. The dietary exposure assessment was made. Results Three PFASs were detected in milk samples which were PFOA, PFUdA, and PFOS. The numbers of detected samples were 5, 12, and 14, respectively. Their concentration ranges were 〈Limit of determination （LOD） -431.94 pg/ml,〈LOD-15.95 pg/ml and〈LOD-126.98 pg/ml, respectively. Three PFAS precursors were also found above the detection limits, namely, 4：2 FTS, 6：2 FTS, and 6：2 diPAP. Only one sample was detected 4：2 FTS at the concentration of 3.75 pg/ml. The detected samples of 6：2 FTS and 6：2 diPAP were 12 and 3. Their concentration ranges were〈LOD-2.49 pg/ml and〈LOD-24.56 pg/ml, respectively. The ranges estimated daily intake of PFOA and PFOS of the detected samples were 2.49×10^-3-405.89×10^-3 ng·kg^-1·d^-1 and 36.10×10^-119.32×10^-3 ng·kg^-1·d^-1. Conclusion Our resuhs suggested that there were different contamination levels of PFASs and their precursors in the 18 market milk produced from different regions in china. The estimated daily intake of PFASs from the milk in our study were far below the tolerable daily intake set by European Union （PFOS： 150 ng·kg^-1·d^-1,PFOA： 1 500 ng·kg^-1·d^-1）.