State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China.
J Chromatogr A. 2018 Apr 6;1544:1-7. doi: 10.1016/j.chroma.2018.02.047. Epub 2018 Mar 2.
In the present study, a highly selective fluorous affinity-based dispersive liquid-liquid microextraction (DLLME) technique was developed for the extraction and analysis of per- and polyfluoroalkyl substances (PFASs) followed by high performance liquid chromatography tandem-mass spectrometry. Perfluoro-tert-butanol with multiple C-F bonds was chosen as the extraction solvent, which was injected into the aqueous samples with a dispersive solvent (acetonitrile) in a 120:800 (μL, v/v) mixture for PFASs enrichment. The fluorous affinity-based extraction mechanism was confirmed by the significantly higher extraction recoveries for PFASs containing multiple fluorine atoms than those for compounds with fewer or no fluorine atoms. The extraction recoveries of medium and long-chain PFASs (CF > 5) exceeded 70%, except perfluoroheptanoic acid, while those of short-chain PFASs were lower than 50%, implying that the proposed DLLME may not be suitable for their extraction due to weak fluorous affinity. This highly fluoroselective DLLME technique can greatly decrease the matrix effect that occurs in mass spectrometry detection when applied to the analysis of urine samples. Under the optimum conditions, the relative recoveries of PFASs with CF > 5 ranged from 80.6-121.4% for tap water, river water and urine samples spiked with concentrations of 10, 50 and 100 ng/L. The method limits of quantification for PFASs in water and urine samples were in the range of 0.6-8.7 ng/L. Furthermore, comparable concentrations of PFASs were obtained via DLLME and solid-phase extraction, confirming that the developed DLLME technique is a promising method for the extraction of PFASs in real samples.
在本研究中，开发了一种基于氟亲和性的高度选择性的分散液相微萃取（DLLME）技术，用于萃取和分析全氟和多氟烷基物质（PFASs），然后采用高效液相色谱串联质谱法进行分析。选择具有多个 C-F 键的全氟叔丁醇作为萃取溶剂，与分散溶剂（乙腈）以 120:800（μL，v/v）的混合物注入水样中，用于 PFASs 富集。通过含有多个氟原子的 PFASs 的萃取回收率明显高于含有较少或没有氟原子的化合物，证实了基于氟亲和性的萃取机制。中长链 PFASs（CF > 5）的萃取回收率超过 70%，除了全氟庚酸，而短链 PFASs 的萃取回收率低于 50%，这表明由于弱氟亲和性，所提出的 DLLME 可能不适合用于它们的萃取。当应用于尿液样品分析时，这种高氟选择性的 DLLME 技术可以大大降低质谱检测中出现的基质效应。在最佳条件下，自来水中 CF > 5 的 PFASs 的相对回收率范围为 10、50 和 100ng/L 加标浓度的 80.6-121.4%。水样和尿样中 PFASs 的方法检出限范围为 0.6-8.7ng/L。此外，通过 DLLME 和固相萃取获得了可比浓度的 PFASs，证实了所开发的 DLLME 技术是一种有前途的用于实际样品中 PFASs 萃取的方法。
