A Highly Selective Extraction Approach for Per- and Polyfluoroalkyl Substances Based on Protein Affinity

Abstract

A selective extraction method with remarkable advantages (i.e., low cost, simplicity, and solvent savings) was developed for the detection of long-chain per- and polyfluoroalkyl substances (PFASs) based on their specific protein affinities. Bovine serum albumin (BSA) was selected to extract PFASs from aqueous samples, which were then desorbed using methanol. Finally, the PFASs were analyzed by high-performance liquid chromatography-tandem mass spectrometry. The optimal extraction conditions were as follows: sample volume, 10 mL; BSA concentration, 2 g/L; equilibration time, 5 min; pH, 3.4; salinity, 6% (w/v) NaCl; and water bath temperature, 80 °C. The protein affinity property was confirmed to be the major extraction mechanism, which significantly increased the selectivity for PFASs. The recoveries of this method for 15 legacy PFASs with CF2 ≥ 6 and three chlorinated polyfluoroether sulfonic acids in tap water, river water, and urine samples with three spiked levels were 73.3-122.3, 83.8-119.4, and 75.0-115.1%, respectively. The method limits of quantification in the three real matrix samples were 4.7-133.3 ng/L. Comparative experiments with conventional solid-phase extraction confirm that the developed approach can be a promising and alternative method for the extraction of PFASs from authentic aqueous samples. Moreover, the proposed method provides a new possibility for screening PFASs exhibiting high bioaccumulation and toxicity.