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 alumina 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 the pesticides decreased linearly with increasing concentration of dioxane in the eluent and they were strongly intercorrelated. The prediction power of TLC for HPLC was low, probably owing to the different pH of the alumina surface. The hydrophilic retention parameters of pesticides determined on alumina supports have a negligible effect on the type of their biological activity (herbicidal, fungicidal, acaricidal or insecticidal).