Gradient elution reversed-phase high-performance liquid chromatography forfractionation of complex mixtures of organic micropollutants according to hydrophobicity using isocratic retention parameters

Gradient elution RP-HPLC is used as a suitable method to infer the hydropho bicity values (log K-ow) of components in complex samples. In this study, t he slope (S) and the intercept (log k(w)) of the linear relationship betwee n the logarithm of the retention factor (log k) and the percentage methanol of the eluent (phi) were first obtained by isocratic runs for a set of mic ropollutants with diverse structures, similar to the contaminants to which the method will be applied. Both S and log k(w) obtained from isocratic run s could be related to log K-ow. Retention times in gradient elution, estima ted from these isocratic parameters as a function of log K-ow, were in very good agreement with experimental values and an almost linear relationship can be established between log K-ow and the retention time. This makes grad ient elution RP-HPLC a suitable method to fractionate complex mixtures acco rding to hydrophobicity. (C) 1999 Elsevier Science B.V. All rights reserved .