Discovery of Iodinated Polyfluoroalkyl Acids by Nontarget Mass-Spectrometric Analysis

Abstract

Per- and polyfluoroalkyl acids (PFAAs) including polyfluoroalkyl carboxylic acids and polyfluoroalkyl sulfonic acids are a large category of crucial environmental pollutants of global concern. Besides known PFAAs, numerous unknown species may exist in the environment, urgently needing discovery and characterization. This study implemented nontarget analysis for a group of novel PFAA pollutants, viz. iodinated PFAAs (I-PFAAs) in wastewater by liquid chromatography-high-resolution mass spectrometry in combination with an iodine-specific data-processing algorithm. The algorithm took into account of the diagnostic fragment iodine ion (I–) together with carbon and sulfur isotopologue distributions. In total, 21 I-PFAA formulas involving 24 congeners were identified. Semiquantification was conducted, and the total concentrations of I-PFAAs were 1.9-311.9 ng/mL, indicating non-negligible pollution of I-PFAAs in the wastewater. The determined concentrations along with predicted environmental behaviors and toxicities demonstrate that I-PFAAs merit further in-depth investigation. The analytical method including the instrumental analysis and data-processing algorithm can be extended to screening and identification of I-PFAAs in other matrices. Furthermore, the analysis results for the first time provide cognition on the occurrence features and pollution status of I-PFAAs in the environment.