One-pot fabrication of magnetic fluorinated carbon nanotubes adsorbent for efficient extraction of perfluoroalkyl carboxylic acids and perfluoroalkyl sulfonic acids in environmental water samples

Efficient extraction of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) is challenging due to their highly fluorinated property. Based on the particular characters of PFCAs and PFSAs, a new type of magnetic fluorinated carbon nanotubes adsorbent (MFCA) for magnetic solid phase extraction (MSPE) was fabricated facilely using one-pot hydrothermal approach. The morphology, structure and magnetic properties of the prepared MFCA were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometry. It was observed that the resultant adsorbent possessed satisfactory superparamagnetism and saturation magnetism. Furthermore, the MFCA exhibited excellent enrichment performance for target PFCAs and PFSAs by means of fluorous-fluorous, hydrophobic and hydrogen bonding interactions. Under the most favorable preparation and extraction conditions, the proposed MFCA/MSPE was combined with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to quantify ultra trace target analyzes in environmental water samples. The limits of detection (S/N = 3) of PFCAs and PFSAs were 0.010-0.036 ng/L and 0.024-0.50 ng/L, respectively. In addition, the introduced approach also displayed other features such as quick extraction procedure, wide linear dynamic ranges, excellent method precision and eco-friendliness. Finally, the concentrations of PFCAs and PFSAs in tap, river, lake and waste water samples were successfully measured by isotope internal standard calibration curve method.