Helmholtz Centre for Environmental Research - UFZ, Department of Analytical Chemistry, Permoserstrasse 15, 04318 Leipzig, Germany.
Helmholtz Centre for Environmental Research - UFZ, Department of Analytical Chemistry, Permoserstrasse 15, 04318 Leipzig, Germany; University of Leipzig, Institute for Analytical Chemistry, Linnéstrasse 3, 04103, Leipzig, Germany.
J Chromatogr A. 2020 Aug 16;1625:461271. doi: 10.1016/j.chroma.2020.461271. Epub 2020 May 29.
Per- and polyfluoroalkyl substances (PFASs) are ubiquitous in the environment. However, only a limited number of predominantly persistent perfluoroalkyl acids (PFAAs) have been analyzed in edible plants so far. We present a generic trace analytical method that allows for quantification of 16 intermediate fluorotelomer alcohol (FTOH)- or perfluoroalkane sulfonamidoethanol (FASE)-based transformation products as well as 18 PFAAs in plants. Additionally, 36 suspected intermediate PFAS transformation products were qualitatively analyzed. The ultrasound-assisted solid-liquid extraction of wheat and maize grain, maize leaves, Jerusalem artichoke and ryegrass (1-5 g plant sample intake) was followed by a clean-up with dispersive solid-phase extraction using graphitized carbon adsorbent (5-10 mg per sample) and chemical analysis by reversed phase liquid chromatography-tandem mass spectrometry. The method was based on matrix matched and extracted calibration and displayed good precision with relative standard deviations in triplicate analyses typically below 15% for all quantified analytes and matrices. An average deviation of 12% between quantified concentrations obtained by matrix matched and extracted calibration and a method based on isotopically labelled internal standards underlines the good trueness of the method. The method quantification limits for the majority of analytes in all plant samples were in the low ng/kg concentration range on a dry weight basis. Plant matrices were analyzed from crops grown on agricultural fields that have been contaminated with PFASs. FTOH- and/or FASE-based intermediate transformation products were detected in all samples with N-ethyl perfluorooctane sulfonamidoacetic acid (EtFOSAA) and perfluorooctane sulfonamide (FOSA) as the prevailing compounds in concentrations up to several hundred ng/kg in maize leaves. The 9:3 Acid (a transformation product of 10:2 FTOH) was tentatively identified. In accordance with these findings, the final degradation products perfluorooctane sulfonic acid (PFOS) and perfluorodecanoic acid (PFDA) were frequently detected. For perfluoroalkyl carboxylic acids (PFCAs), according to earlier findings, short chain homologues generally displayed the highest levels (up to 98 µg/kg for perfluorobutanoic acid (PFBA) in maize leaves). However, maize grain was an exception showing the highest concentrations for long chain PFCAs, whereas PFBA was not detected. The uptake of high levels of PFASs into plants is of concern since these may be used as animal feed or represent a direct exposure medium for humans.
全氟和多氟烷基物质（PFASs）在环境中无处不在。然而，迄今为止，仅对可食用植物中少数主要持久性全氟烷基酸（PFAAs）进行了分析。我们提出了一种通用的痕量分析方法，可定量分析 16 种中间氟调聚物醇（FTOH）或全氟烷基亚磺酰胺基乙醇（FASE）衍生的转化产物以及 18 种 PFAAs。此外，还对 36 种疑似中间 PFAS 转化产物进行了定性分析。通过超声辅助固液萃取，从小麦和玉米籽粒、玉米叶片、菊芋和黑麦（1-5 克植物样本摄入量）中提取，然后用石墨化碳吸附剂（每份样品 5-10 毫克）进行分散固相萃取净化，并通过反相液相色谱-串联质谱进行化学分析。该方法基于基质匹配和提取校准，在所有定量分析物和基质中，三重分析的相对标准偏差通常低于 15%，显示出良好的精密度。在使用基质匹配和提取校准以及基于同位素标记内标物的方法获得的定量浓度之间平均偏差为 12%，这强调了该方法的良好准确性。该方法在所有植物样本中的大多数分析物的定量限都在低 ng/kg 浓度范围内，以干重为基础。植物基质来自农田种植的作物，农田已被 PFAS 污染。在所有样品中均检测到基于 FTOH 和/或 FASE 的中间转化产物，其中 N-乙基全氟辛烷磺酰胺基乙酸（EtFOSAA）和全氟辛烷磺酰胺（FOSA）是主要化合物，浓度高达数百 ng/kg，存在于玉米叶片中。9:3 酸（10:2 FTOH 的转化产物）被初步鉴定。根据这些发现，经常检测到最终降解产物全氟辛烷磺酸（PFOS）和全氟癸酸（PFDA）。对于全氟烷基羧酸（PFCAs），根据早期的研究结果，短链同系物通常显示出最高水平（在玉米叶片中，高达 98 µg/kg 为全氟丁酸（PFBA））。然而，玉米籽粒是一个例外，长链 PFCAs 的浓度最高，而未检测到 PFBA。植物对高水平 PFAS 的吸收令人担忧，因为这些物质可能被用作动物饲料或直接成为人类的暴露介质。
