Comparison of Adsorption Coefficient (K_OC) for Soils and HPLC Retention Factors of Aromatic Hydrocarbons Using a Chemically Immobilized Humic Acid Column in RP-HPLC

Abstract

The determination of soil adsorption coefficients (K_OC) via HPLC capacity factors (k′) has been studied, including the effect of column type and mobile phase composition on the correlation between log K_OC and log k′. K_OC values obtained by procedures other than HPLC correlate well with HPLC capacity factors determined on a chemically immobilized humic acid stationary phase, and it is suggested that this phase is a better model for the sorption onto soil or sediment than the octadecyl-, phenyl- and ethylsilica phases. By using log k′_w a theoretical capacity factor has been obtained by extrapolation of the retention data in a binary solvent system to pure aqueous eluent. There is a better correlation between log K_OC and log k′_w than the correlation between log K_OC and log k′.