Extraction of triallate from soil with supercritical carbon dioxide and determination by gas chromatography atomic emission detection - Comparison with a solvent extraction procedure

The potential of supercritical CO2 for the extraction of triallate from soil as an alternative to a conventional acetonitrile extraction procedure is investigated, Triallate is extracted at a density of 0.65 g/ml, an equilibrium time of 8 min, an extraction time of 25 min and a flow-rate of 1 ml/min. The extract is collected on an octadecylsilane trap at 5 degrees C and eluted with 1 mi of acetonitrile. The analyte is determined by capillary gas chromatography with atomic emission detection. The validity of the supercritical fluid extraction method is rested on spiked and real soils. The triallate concentrations obtained on aged soils are lower applying supercritical fluid extraction with pure CO2 than applying solvent extraction, making necessary the use of CO2 modified with methanol to achieve similar results.