Oak Ridge Institute for Science and Education, National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, United States.
J Chromatogr A. 2018 May 25;1551:52-58. doi: 10.1016/j.chroma.2018.03.047. Epub 2018 Mar 23.
Legacy perfluorinated compounds exhibit significant environmental persistence and bioaccumulation potential, which has spawned an ongoing effort to introduce replacement compounds with reduced toxicological risk profiles. Many of these emerging chemical species lack validated quantitative methods, and, frequently, appropriate analytical standards for accurate monitoring and identification. To fill this knowledge gap, a general method for the quantitative determination of perfluoroether carboxylic acids (PFECAs) by LC-MS/MS was single-lab validated on spike-recovery samples in surface, drinking, and wastewater for a variety of perfluorinated ether standards. Relative error measurements for spike-recovery samples in each matrix ranged from 0.36% to 25.9%, with an average error of 10% overall. Coefficient of variation (CV) for each compound ranged from 10 to 28% with an average of 17%. The quantitative methodology was applied during repeated weekly monitoring of the Cape Fear River during remediation of PFECA hexafluoropropyloxide dimer-acid (HFPO-DA), known by the brand name "GenX." Semi-quantitative concentration estimates for emerging PFECA compounds lacking analytical standards was also carried out using surrogate calibration curves and mass labeled HFPO-DA as an internal standard. Estimates of the emerging compounds were possible using matched standards, but application of the estimation methodology to compounds with known concentration revealed that such estimates may possess up to an order of magnitude, or more, in uncertainty due to the difficulty of matching with an appropriate standard. Nevertheless, the estimation biases are primarily systematic (extraction efficiency and instrument response) rather than stochastic, enabling the collection of time-course data; both HFPO-DA and the emerging compounds were reduced in surface water and drinking water concentration of several orders of magnitude after removal of the source waste stream.
传统的全氟化合物具有显著的环境持久性和生物累积潜力，这促使人们不断努力引入毒性风险较低的替代化合物。许多新兴的化学物质缺乏经过验证的定量方法，并且经常缺乏用于准确监测和识别的适当分析标准。为了填补这一知识空白，在表面、饮用水和废水中，对各种全氟醚标准进行了单实验室验证，建立了一种通过 LC-MS/MS 定量测定全氟醚羧酸 (PFECA) 的通用方法。每种基质中加标回收率样品的相对误差测量值在 0.36%至 25.9%之间，平均误差为 10%。每个化合物的变异系数 (CV) 范围为 10%至 28%，平均为 17%。在对 Cape Fear 河进行的 PFECA 六氟丙氧基二羧酸 (HFPO-DA) 修复过程中的每周重复监测中应用了定量方法，该物质的商品名为“GenX”。对于缺乏分析标准的新兴 PFECA 化合物，还使用替代校准曲线和质量标记的 HFPO-DA 作为内标进行了半定量浓度估算。使用匹配的标准可以对新兴化合物进行估计，但将该估计方法应用于具有已知浓度的化合物时，由于与适当标准匹配的困难，这些估计可能存在一个数量级或更多的不确定性。然而，估计偏差主要是系统性的（提取效率和仪器响应）而不是随机性的，从而能够收集时间过程数据；在去除源废水后，HFPO-DA 和新兴化合物在地表水和饮用水中的浓度都降低了几个数量级。
