A rapid in-situ method based on liquid-phase nanoextraction for the determination of perfluorinated compounds in cerebrospinal fluid.

Perfluorinated compounds (PFCs) are emerging pollutants with strong bioaccumulation and stability, and potential risks to human health. Biological samples are usually limited in volume and content trace levels of target analytes, thus requiring in-situ and minimally invasive detection techniques (such as solid-phase microextraction (SPME), microfluidic chip analysis, and in vivo sampling). However, conventional detection methods are difficult to achieve accurate qualitative and quantitative analysis of trace PFCs. In this study, a rapid, in-situ and green analytical method was developed by combining nanoconfined liquid phase nanoextraction (NLPNE) with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of 9 PFCs in cerebrospinal fluid. The interlaced carbon nanofibers (CNFs) form multi-dimensional network nanopores, which provide favorable structural basis for the construction of NLPNE systems. The carbon nanofibers/carbon fibers (CNFs/CFs) was used to confined methanol, which was packed into the needle tip to fabricate a portable needle-tip extraction device. The confined methanol enhanced the extraction efficiency of 9 PFCs. Key parameters affecting extraction performance were optimized (including confined fluid type and volume, extraction time, desorption solvent type and desorption time). Under optimal conditions, the method exhibited excellent linearity (r ≥ 0.9955) in the range of 0.1-500 μg L-1, with method limits of detection (MDLs) and limits of quantification (MQLs) ranging from 0.15 to 7.5 μg L-1 and 0.50 to 24.98 μg L-1, respectively. The intra-day and inter-day relative standard deviations (RSDs) were ≤12.99%, and the recovery of PFCs in cerebrospinal fluid samples was 70.56%-119.12% with RSD ≤11.63%. Compared with traditional methods, this method has the advantages of short time, small organic solvent, and simple operation ability, providing a novel and reliable approach for the real-time rapid analysis of trace PFCs in small-volume complex biological samples.