SUPERCRITICAL-FLUID EXTRACTION OF S-TRIAZINES AND PHENYLUREA HERBICIDES FROM SEDIMENT

s-Triazines and phenylurea herbicides were recovered from spiked sediment using supercritical fluid extraction (SFE). The effects of important experimental variables such as extraction temperature, time of extraction, and supercritical fluid density were investigated. Analyte recovery was low and variable using unmodified supercritical carbon dioxide but could be significantly improved as a result of acetone modification. SFE was much faster than Soxhlet extraction for the determination of these priority pollutants and was advantageous in terms of improved analyte recovery and reduced solvent and labor requirements. Thermally labile phenylurea herbicides also proved to be less susceptible to thermal degradation using the SFE technique.