RELATIONSHIP BETWEEN THE HIGH-PERFORMANCE LIQUID AND THIN-LAYER CHROMATOGRAPHIC RETENTION OF NONHOMOLOGOUS SERIES OF PESTICIDES ON AN ALUMINA SUPPORT

The retentions of 26 commercial pesticides were determined on an alumi na HPLC column and in TLC carried out on alumina layers using n-hexane -dioxane mixtures as eluents. Both the log k'(O) and R(MO) values of t he pesticides decreased linearly with increasing concentration of diox ane in the eluent and they were strongly intercorrelated. The predicti on power of TLC for HPLC was low, probably owing to the different pH o f the alumina surface. The hydrophilic retention parameters of pestici des determined on alumina supports have a negligible effect on the typ e of their biological activity (herbicidal, fungicidal, acaricidal or insecticidal).