Soil column chromatography for correlation between capacity factors and soil organic partition coefficients for eight pesticides.

A soil column chromatographic method was developed to measure the capacity factors (k′) of pesticides, in which soil acted as a stationary phase and methanol-water mixture as an eluent. The k′ values of eight pesticides, including three insecticides (methiocarb, azinphos-methyl, fenthion), four fungicides (triadimenol, fuberidazole, tebuconazole, pencycuron), and one herbicide (atrazine), were found to be well fitted to a retention equation, ln k′ = ln k′w-Sθ. Due to similar interactions of solutes with soil and solvent in both sorption determination and retention experiment, log k′ has a good linear correlation with log Koc for the eight pesticides from different classes, in contrast with poor correlation between log k′ from C18 column and log Koc. So the method provides a tool for rapid estimation Koc from experimental k′