Fig. 6: KMD analysis of polyfluoroalkyl substances before and after chlorination.
KMD plots are shown for features with masses normalized to CF2 units, highlighting changes in molecular composition during chlorination of an AFFF sample (#3-398). a shows KMD profiles acquired in positive ionization mode. b shows KMD profiles acquired in negative ionization mode. Solid black circles labeled “CK” represent the Kendrick mass profiles of polyfluoroalkyl substances prior to chlorination and serve as baseline references. Open symbols represent the corresponding features after chlorination, with different time points ranging from 1 to 96 h. The shift and evolution of points over time indicate chemical transformations occurring during the chlorination process.
