The log Kkao/w of BACs at low concentration (Ckao = 100 μmol/kg) increased with alkyl chain length, but the increase in log Kkao/w per -CH2-varied with chain length. For example, log Kkao/w increases by only 0.2 log units from C6-BAC to C8-BAC but by 0.8 log units from C12-BAC to C14-BAC.