Gas chromatographic/mass spectrometric determination of flumioxazin extracted from soil and water

A method was developed for determining flumioxazin in soil and water. Recovery efficiencies for solid-phase extraction (SPE) of flumioxazin from deionized, well, and surface water were between 72 and 77%. SPE was superior to liquid-liquid extraction, using water-hexane and water-chloroform emulsions, which resulted in retrieval efficiencies of 25 and 22%, respectively. However, liquid-liquid extraction with ethyl acetate improved recovery of total flumioxazin to >64%. Extraction from soil samples by direct solvent/soil extraction methods recovered between 18 and 76% of applied flumioxazin, depending on the solvent combination used. However, the use of accelerated solvent extraction techniques resulted in a 106 +/- 8% recovery of flumioxazin from soil. In analysis by capillary gas chromatography with mass selective detection, flumioxazin had a calculated limit of detection of 9 ng/mL with a retention time of 16.66 min.