Automated Pressurized Liquid Extraction and Sample Clean Up of River Sediment in POPs Analysis

Oral Presentation

Prepared by R. Addink, M. Falkenstein
Toxic Report LLC, 580 Pleasant St, 2nd Fl, Watertown, MA, 02472, United States

Contact Information:; 617-393-1713


Persistent organic pollutants (POPs) such as polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs) and biphenyls (PCBs) have been a major environmental concern for a number of decades. Due to their low solubility in water and their resistance to breakdown, they tend to accumulate in river sediment. Analyses of sediment samples using US EPA methods 1613 (PCDD/Fs) and 1668 (PCBs) have been carried out around the world. Study of sediments often involves large amounts of samples, making fast processing (extraction, clean up, analysis) all the more important. This work describes the automated Pressurized Liquid Extraction (PLE) and automated open column chromatography clean-up of river sediment. Quick and easy processing results in samples being ready for same-day analysis.

1g of sample was mixed with Hydromatrix™ and spiked with 13C labeled standards. Samples were put in extraction cells. Pressurized Liquid Extraction with 50%/50% v/v dichloromethane/hexane (120oC, 1500psi, 20min) was carried out. Clean-up was done with automated column chromatography, using jumbo silica, classical ABN, alumina and carbon/celite columns. Solvent mixes used were hexane, 2%/98% dichloromethane/hexane, 50%/50% dichloromethane/hexane, 50%/50% ethylacetate/benzene, and toluene. Samples were analyzed with high-resolution GC/MS.

13C PCDD/F recoveries varied between 82%-105% and between 93%-125% for PCBs. A certified reference sample of NIST river sediment with known composition was analyzed. Excellent agreement was found between native values of both PCDD/F and PCBs measured and the reference values provided.

Extraction, clean up and analysis by properly trained personnel can be carried out in one day, resulting in low turnaround times.