The F number is a molecular size descriptor proposed by Hurtubise et al. as follows: F= (number of double bonds) + (number of primary and secondary carbons) - 0.5 x (number of non-aromatic rings), and a high linear correlation between log k' and F number was found in aqueous reversed-phase LC.
Reference: J.F.Schabron, R.J.Hurtubise and H.F.Silver, Anal. Chem., 49, 2253(1977).
Most recent update: Mar/1/1996.