Department of Chemistry, University of Florida, Gainesville, FL, USA.
College of Veterinary Medicine, Department of Physiological Sciences, University of Florida, Gainesville, FL, USA.
Sci Total Environ. 2021 Mar 15;760:143944. doi: 10.1016/j.scitotenv.2020.143944. Epub 2020 Dec 4.
Specific aspects of previously reported extraction workflows, for measurement of per- and polyfluoroalkyl substances (PFAS) in solid matrices, have not been adequately interrogated. The objective of this study was to explore the importance of each workflow step in providing the most appropriate extraction for a comprehensive set of PFAS (51 different species) in soil. We compared different procedures, including two pre-extraction set ups (overnight handling of samples prior to extraction), two extraction solvents (methanol (MeOH), and acetonitrile (ACN)), two extraction solvent volumes (10 mL and 8.5 mL), and two post-extraction cleanup strategies (ENVI-Carb and ion-pair). Of the 51 species targeted, 21 were at quantifiable levels in soil samples collected adjacent to a landfill, of which 13 PFAS were consistently detected among the different extraction workflows. Overall, results showed no significant difference in PFAS concentration between different extraction solvents and cleanup strategies. Perfluoropentanoic acid, perfluorohexanoic acid, and perfluorooctanoic acid had the highest concentrations in all extraction workflows, accounting for nearly 13%, 38%, and 17% of the total monitored PFAS (ΣPFAS), respectively. While final concentration values were similar across methods, recovery and accuracy studies showed that MeOH had the best recovery, with 88% of the isotopically labeled PFAS standards showing extraction recovery within the acceptable range of 80% to 120% (compared to 14% of isotopically labeled PFAS standards in workflows using ACN). Upon examination of additional cleanup steps, 67% of monitored PFAS (out of 51 total PFAS monitored), on average, exhibited higher accuracy (relative error ≤20%) using ENVI-Carb clean up (in comparison with 51% in workflows using ion pair clean up). Results also demonstrated that larger volumes of MeOH (and subsequent re-extractions) did not yield a better recovery, enabling a reduction in overall analysis time and cost in comparison to many published methods.
先前报道的萃取工作流程的具体方面，用于测量固体基质中的全氟和多氟烷基物质（PFAS），尚未得到充分探讨。本研究的目的是探讨每个工作流程步骤在提供最适合的萃取方面的重要性，以涵盖土壤中一组全面的 PFAS（51 种不同物质）。我们比较了不同的程序，包括两种预萃取设置（在萃取前过夜处理样品）、两种萃取溶剂（甲醇（MeOH）和乙腈（ACN））、两种萃取溶剂体积（10mL 和 8.5mL），以及两种萃取后清洁策略（ENVI-Carb 和离子对）。在所采集的紧邻垃圾填埋场的土壤样本中，可检测到 51 种目标物质中的 21 种，其中 13 种 PFAS 在不同的萃取工作流程中始终被检测到。总体而言，不同萃取溶剂和清洁策略之间的 PFAS 浓度没有显著差异。全氟戊酸、全氟己酸和全氟辛酸在所有萃取工作流程中的浓度最高，分别占监测到的总 PFAS（ΣPFAS）的近 13%、38%和 17%。尽管各方法的最终浓度值相似，但回收率和准确性研究表明，MeOH 的回收率最好，88%的同位素标记 PFAS 标准品的萃取回收率在可接受的 80%至 120%范围内（相比之下，使用 ACN 的工作流程中 14%的同位素标记 PFAS 标准品的萃取回收率）。在对其他清洁步骤进行检查后，67%（51 种总监测的 PFAS 中的 33 种）平均表现出更高的准确性（相对误差≤20%），使用 ENVI-Carb 清洁（相比之下，使用离子对清洁的工作流程中 51%的准确性）。结果还表明，更大体积的 MeOH（和随后的再萃取）并没有提高回收率，与许多已发表的方法相比，可减少整体分析时间和成本。
