The final adjusted solute descriptors for all PFAS are presented in Table , and those for selected PFAS are shown in Table . The system parameters for all GC columns and partition systems are given in Table . All five solute descriptors are now available for 47 neutral PFAS. For the remaining 13 PFAS, the values of S, A, V, and L are available, but the value of B is missing due to lack of K data. The quality of solute descriptor fitting was high, with SDs generally < 0.1 log units. The relatively high SDs (0.1-0.5) were obtained only for PFAs, FEs, and perfluorotrialkylamines (PFTAAs), suggesting that the uncertainty of the descriptor values for these PFAS may be high. The reason for the low fit is currently unknown but could be related to the particularly high degree of fluorination of these PFAS, with little or no nonfluorinated substructure in the molecules.