Determination of the relative impact of chromatographic conditions and solute structures on the retention behaviour of non-ionic surfactants in RP-HPLC

The retention behaviour of non-ionic surfactants containing different hydro phobic moiety and various lengths of polar ethylene oxide chain was studied on RP-8 and RP-18 columns using methanol and acetonitrile as organic modif iers. The relative impact of the chromatographic conditions on the retentio n strength was determined using stepwise regression analysis. Non-ionic sur factants can be separated according to the character of the hydrophobic moi ety, but not according to the length of the polar ethylene oxide chain. Cal culations proved that the organic modifier exerted the highest impact on th e retention; the effect of the number of carbon atoms in the hydrophobic mo iety, column temperature and the length of the hydrophobic ligand on the su rface of silica support are of secondary importance. Copyright (C) 1999 Joh n Wiley & Sons, Ltd.