Department of Chemistry, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada.
Department of Chemistry, Memorial University, St. John's, Newfoundland and Labrador A1B 3X7, Canada.
Anal Chem. 2023 May 16;95(19):7648-7655. doi: 10.1021/acs.analchem.3c00593. Epub 2023 May 3.
Ultrashort-chain perfluorinated carboxylic acids (PFCAs) are receiving more attention due to their ever-increasing presence in the environment. Methods have been established for the analysis of short- and long-chain PFCAs, while robust quantitation of ultrashort-chain species is scarce. Here, we develop a novel derivatization method using diphenyl diazomethane for quantitation of C2-C14 PFCAs in aqueous matrices. The method is highlighted by rapid completion of derivatization (<1 min) and retention and separation of ultrashort-chain (C2/C3) PFCA derivatives using H carrier gas ( > 1.5). A weak anion exchange solid-phase extraction procedure for analyte recovery from representative aqueous samples was developed and validated by spike and recovery from ultrapure water, synthetic ocean water, and simulated denuder extracts used for collecting gaseous PFCAs. Recoveries for PFCAs ranged from 83 to 130% for the majority of analytes and matrices. The instrument detection limits (IDLs) range from 8 to 220 fg per injection, and method detection limits (MDLs) range from 0.06 to 14.6 pg/mL for 500 mL aqueous samples, which are within an order of magnitude to conventional LC-MS/MS methods. The method was applied to the analysis of real samples of tap water, rainwater, ocean water, and annular denuder extracts. The overall method provides a cost-effective alternative to conventional LC-MS/MS methods, overcoming the typical GC-MS drawbacks of high detection limits and long sample preparation times while being able to simultaneously analyze the complete spectrum of environmentally relevant PFCAs.
由于超短链全氟羧酸（PFCAs）在环境中越来越普遍，因此受到了更多的关注。目前已经建立了用于分析短链和长链 PFCAs 的方法，而对超短链物质的定量分析却很少。在这里，我们开发了一种使用二苯重氮甲烷的新衍生化方法，用于定量分析水基质中的 C2-C14 PFCAs。该方法的特点是衍生化速度快（<1 分钟），使用 H 载气（>1.5）保留和分离超短链（C2/C3）PFCA 衍生物。建立了一种从代表性水样品中回收分析物的弱阴离子交换固相萃取程序，并通过从超纯水、合成海水和用于收集气态 PFCAs 的模拟沉降器提取物中进行加标和回收来验证。对于大多数分析物和基质，PFCAs 的回收率在 83%至 130%之间。仪器检测限（IDL）范围为 8 至 220 fg/进样，对于 500 mL 水样品，方法检测限（MDL）范围为 0.06 至 14.6 pg/mL，与传统的 LC-MS/MS 方法相当。该方法应用于自来水、雨水、海水和环形沉降器提取物的实际样品分析。该方法为传统 LC-MS/MS 方法提供了一种具有成本效益的替代方法，克服了 GC-MS 检测限高和样品制备时间长的典型缺点，同时能够同时分析环境相关 PFCAs 的完整谱。
