M. Balcan et Df. Anghel, Retention behavior of ethoxylated nonionic surfactants with different hydrophobic moieties by RP-HPLC, REV RO CHIM, 43(11), 1998, pp. 1043-1047
The retention behavior of polydisperse ethoxylated fatty alcohols with the
same ethoxylation degree but various alkyl chain lengths (CnEO10, n = 12, 1
4, 16 and 18) has been investigated by reversed-phase high-performance liqu
id chromatography (RP-HPLC) as a function of methanol content of the mobile
phase. The linear correlation between the logarithm of capacity factor, lo
w k', and the eluent composition was used to determine the standard hydroph
obicity parameter, k(w). The change of k(w) with the alkyl chain length of
surfactants resulted in a value of -2.81 kJ/mol for the free energy of tran
sferring one methylene group from water to nonpolar stationary phase. This
value is in agreement with the reported value of about -2.85 kJ/mol obtaine
d from micellization data for the same surfactants.