Use of acetonitrile for the extraction of herbicide residues from soils.

Using a 10% aqueous acetonitrile solution for extraction and an identical solvent clean-up procedure, soil-based residues of the herbicides alachlor, benzoyl-prop-ethyl, flufenprop-isopropyl, flufenprop-methyl, dichlorfop-methyl, nitrofen, and profluralin were recovered reproducibly from three prairie soils fortified at 0.5 and 0.1 ppm levels. The acidic herbicides benazolin, 2,4-D, and 2,4,5-T, together with the acids derived from benzoylprop-ethyl, dichlorfop-methyl, flufenprop-isopropyl, and flufenprop-methyl were reproducibly recovered from the three prairie soils fortified at 0.5 and 0.1 ppm levels using 30% aqueous acetonitrile containing 1% acetic acid after identical clean-up stages. All compounds were analysed by gas chromatographic means utilising an electron-capture detector. The two procedures described were developed for the routine extraction and analysis of neutral and acidic herbicide residues from field soil persistence studies.