Independent mode sorption of perfluoroalkyl acids by single and multiple adsorbents.

Infinite dilution partition coefficients, , of a series of unbranched perfluoralkylacids, PFAAs with 3 to 8 CF units between water and commercially available weak anion exchange (WAX) and strong anion exchange (MAX) polymers, C-modified silica, hydrophilic-lipophilic balance polymer (HLB), and AlO sorbents were determined with self-packed columns using an HPLC-MS/MS setup. The anionic WAX sorbent shows a much higher adsorption affinity (about 450 fold) for PFBA than was observed for the applied hydrophobic sorbent HLB. Since the incremental value for each CF group is smaller when the electrostatic adsorption process is observed, the hydrophobic partition coefficient of HLB supersedes the electrostatic one of WAX at around PFTeDA.