A rapid and sensitive HPLC procedure for the determination of atrazine residues in soil-water extracts.

An automated procedure is described for the rapid determination of the residual herbicide atrazine at ppb levels in soil-water extracts. The system consists of an autosampler connected to a C18 precolumn linked via a switching valve to a C18 analytical column and spectrophotometer. Peak height is superior to peak area for quantifying results with coefficients of variation of 0.48% and 0.89%, respectively, for 7.5 ng standard injections. Precolumn concentration eliminates the need for sample cleanup and achieves up to a 37% increase in peak height compared to an isocratic system. In a black earth soil, atrazine is identified as the principal phytotoxic constituent. The minimum detectable level is one-tenth the critical no-effect threshold for wheat. The method is well suited for predicting possible atrazine injury to susceptible crops and the measurement of other nonpolar analytes in aqueous solution.