HPLC-screening method to determine the adsorption coefficient in soil-comparison of immobilized humic acid and clay mineral phases for cyanopropyl columns

An HPLC-screening method for the determination of the adsorption coefficient on soil is established. Humic acids and clay minerals which are sorption relevant soil constituents, were immobilized on silicagel phases and used as stationary phases in HPLC-columns. These stationary phases were tested with 50 test substances. For these test substances reliable KOC-values were available generated according to the OECD testguideline [1]. Commercial cyanopropyl columns and humic acid columns revealed comparable results indicating that the well defined synthetic stationary phase is able to simulate sorption capacities of soils. The retention capacity of immobilized clay mineral columns was very low for most of the test substances indicating that, for most organic substances, clay minerals are of less importance in sorption processes.