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

The determination of soil adsorption coefficients (K-oc) via HPLC capa city factors (k') has been studied, including the effect of column typ e 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 octadecy l-, phenyl- and ethylsilica phases. By using log k', a theoretical cap acity factor has been obtained by extrapolation of the retention data in a binary solvent system to pure aqueous eluent. There is a better c orrelation between log K-oc and log k'(w) than the correlation between log K-oc and log k'.