EVALUATION OF SAMPLE PREPARATION PROCEDURES FOR THE DETERMINATION OF ORGANIC MICROPOLLUTANTS IN RIVER SEDIMENTS.

Different sample preparation methods for the determination of organic micropollutants in river sediments are compared and evaluated. Sediment samples were spiked and the wet, chemically dried or freeze-dried materials were extracted using methods such as Soxhlet extraction,ultrasonic agitation, shaking and stirring with solvent and steam distillation. The extractions were performed with both methylene chloride and cyclohexane on different sediments. This study has shown that for the determination of polyaromatic hydrocarbons, the best results were obtained from freeze-dried sediment using ultrasonic agitation (70 % recovery) or stirring (77 %) with methylene chloride.