Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3 - 50019 Sesto Fiorentino, Florence, Italy.
Department of Chemistry, University of Turin, Via Pietro Giuria 5 - 10125 Turin, Italy.
J Chromatogr A. 2020 Jun 21;1621:461038. doi: 10.1016/j.chroma.2020.461038. Epub 2020 Mar 14.
A QuEChERS method was optimized and validated for the LC-MS/MS analysis of perfluoro-n-pentanoic acid (PFPeA), perfluoro-1-butanesulfonic acid (PFBuS), perfluoro-n-hexanoic acid (PFHxA), perfluoro-n-heptanoic acid (PFHpA), perfluoro-1-hexanesulfonic acid (PFHxS), perfluoro-n-octanoic acid (PFOA), perfluoro-n-nonanoic acid (PFNA), perfluoro-1-octanesulfonic acid (PFOS) and perfluoro-n-decanoic acid (PFDA) in freeze-dried strawberry and olive, as model fruits characterized by very different chemical compositions. The method was evaluated for apparent recovery, intra-day and inter-day precision, matrix effect and recovery. The method optimized for strawberry provided for most compounds absolute values of matrix effect (|ME%|) ≤ 11%, except for PFHxA, which showed a signal suppression of 22%. The extraction efficiency was tested at the spike levels 500-5000 pg/g d.w. for PFPeA, PFBuS, and PFHxA, and 100-1000 pg/g d.w. for the other target analytes, evidencing as a whole recoveries in the range of 65-89%. For olive fruits, due to their high fat content, an ultrasound-assisted extraction was necessary to obtain an efficient sample disgregation so as to increase the extraction yield and its precision. Moreover, a d-SPE clean-up with GCB allowed to achieve |ME%| ≤ 8% (except for PFBuS, which showed a signal enhancement of 19%) and recoveries calculated at the aforementioned spike levels were in the range 75-97%. The two methods provided very good linearity (R ≥ 0.9984) from 10,000 pg/g down to compound specific quantification limits, which were included in the ranges of 2.9-393 pg/g and 2.6-127 pg/g for strawberry and olive fruit, respectively. The methods were applied to the analysis of PFAAs in strawberry and olive fruits commercially available in two Italian supermarkets, as well as obtained under irrigation with various treated wastewaters (TWWs), evidencing in both cases a higher PFAAs occurrence in olives than in strawberry. However, PFAAs concentrations determined in the investigated fruit matrixes were quite low, being their sum 1.9 ng/g d.w. in the worst case (i.e. olive fruits grown under irrigation with TWWs).
建立了固相萃取-超高效液相色谱串联质谱法（QuEChERS-UPLC-MS/MS）同时测定冷冻干燥草莓和橄榄油中 7 种全氟羧酸（PFCAs）和 2 种全氟磺酸（PFSAs）的分析方法。方法以具有不同化学性质的草莓和橄榄油为模型水果，优化并验证了前处理条件和色谱质谱参数。在草莓中，除了全氟己烷磺酸（PFHxS）的基质效应（ME%）为-22%，其他目标物的 ME%绝对值均小于 11%。在 500-5000 pg/g（干重，d.w.）范围内，除了全氟癸酸（PFDA），其他目标物的回收率均在 65%-89%之间；在橄榄油中，由于其脂肪含量较高，需要采用超声辅助提取，以提高提取效率和重现性。此外，采用石墨化炭黑（GCB）净化，可将 ME%绝对值控制在 8%以内（除了全氟丁烷磺酸，其 ME%为 19%），各目标物的回收率在 75%-97%之间。该方法在 10000 pg/g 至各化合物定量限范围内具有良好的线性（R2≥0.9984），草莓和橄榄油的定量限分别为 2.9-393 pg/g 和 2.6-127 pg/g。该方法应用于 2 家意大利超市市售草莓和橄榄油以及不同处理污水（TWW）灌溉的草莓和橄榄油中全氟化合物（PFAAs）的检测，结果表明，与草莓相比，橄榄油中 PFAAs 的含量更高。然而，在所研究的水果基质中，PFAAs 的浓度相当低，在最不利的情况下（即 TWW 灌溉的橄榄油），其总浓度为 1.9 ng/g（干重）。
