A matrix effect-free method for reliable quantification of perfluoroalkyl carboxylic acids and perfluoroalkane sulfonic acids at low parts per trillion levels in dietary samples.
A matrix effect-free method for reliable quantification of perfluoroalkyl carboxylic acids and perfluoroalkane sulfonic acids at low parts per trillion levels in dietary samples.
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DOI：
10.1016/j.chroma.2012.03.023
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发表时间：
2012-05
期刊：
影响因子：
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通讯作者：
R. Vestergren;S. Ullah;I. Cousins;U. Berger
中科院分区：
文献类型：
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作者：
R. Vestergren;S. Ullah;I. Cousins;U. Berger
在最近的接触模拟研究中，饮食已被确定为人类接触全氟辛酸（PFOA）和全氟辛烷磺酸（PFOS）的主要途径。然而，缺乏高度敏感和准确的分析数据来支持这些研究，这意味着他们的结论值得商榷。本文描述了一种新的无基质效应的方法，用于超痕量分析不同组成的膳食样品中的全氟烷基羧酸和全氟烷烃磺酸。该方法采用离子对萃取法将分析物萃取到甲基叔丁基醚中，然后在Florisil和石墨化碳上进行固相萃取净化。目的化合物采用超高效液相色谱-串联质谱法进行分离和检测。特别注意避免程序空白污染和潜在的污染源。该方法的性能验证了五种不同的食品测试基质，包括一个重复的饮食样本。所有目标分析物的检测限均在低至亚pgg - 1范围内，灵敏度比先前报道的重复饮食样品高5-100倍。在所有测试的食品基质中，所有分析物的总方法回收率始终在50%到80%之间，并且发现共提取基质成分对目标化合物电离的影响可以忽略不计。该方法的精密度（定义为相对标准偏差百分比）在浓度接近各自的方法定量限时，所有分析物的精密度<15%。在超痕量水平的精确定量证明了实验室控制脉冲实验。这是首次报道在重复的饮食样品中存在长链PFCAs。因此，本文提出的方法可以支持改进人类从饮食摄入中暴露于PFCA和PFSA同源物的评估。对先前使用另一种分析方法分析的重复饮食样本的重新分析表明，以前可能高估了全氟辛烷磺酸和全氟辛烷磺酸的饮食摄入量。
In recent exposure modeling studies diet has been identified as the dominant pathway of human exposure to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). However, the paucity of highly sensitive and accurate analytical data to support these studies means that their conclusions are open to question. Here a novel matrix effect-free method is described for ultra-trace analysis of perfluoroalkyl carboxylic acids and perfluoroalkane sulfonic acids in dietary samples of varied composition. The method employs ion pair extraction of the analytes into methyl tert-butyl ether and subsequent solid phase extraction clean-up on Florisil and graphitized carbon. The target compounds are separated and detected using ultra performance liquid chromatography coupled to tandem mass spectrometry. Special care was taken to avoid procedural blank contamination and potential contamination sources were elucidated. The performance of the method was validated for five different food test matrices including a duplicate diet sample. Method detection limits in the low to sub pgg−1range were obtained for all target analytes, which is 5–100 times more sensitive than previously reported for duplicate diet samples. Total method recoveries were consistently between 50 and 80% for all analytes in all tested food matrices and effects of co-extracted matrix constituents on ionization of the target compounds were found to be negligible. The precision of the method (defined as percentage relative standard deviation) at concentrations close to the respective method limits of quantification was <15% for all analytes. Accurate quantification at ultra-trace levels was demonstrated by laboratory control spike experiments. For the first time the presence of long-chain PFCAs in duplicate diet samples is reported. The method presented here can thus support an improved assessment of human exposure from dietary intake for a range of PFCA and PFSA homologues. Re-analysis of duplicate diet samples, which had been analyzed earlier using another analytical methodology, indicated that dietary intake of PFOA and PFOS may previously have been overestimated.