Abstract
A method for the determination of trace amounts of the organophosphorus insecticide dimethoate in waste water, soil and sediment is presented. Sediment and soil samples are extracted by soxhelt with acetone/hexane followed by partition of the extract between methylene chloride and water. Separation of dimethoate from other compounds is carried out using gel permeation chromatography with Bio-Beads SX-3. Dimethoate is determined by capillary gas chromatography with a nitrogen-phosphorus detector. Detection limits are 10, 30 and 130ppt for surface water, waste water and soil/sediment respectively. Recoveries are 70.6–75.2% with standard deviations between 5.4 and 9.2%.