Rapid Determination of Persistent Organic Pollutants (POPs) Using Accelerated Solvent Extraction (ASE)

INTRODUCTION The United Nations Environmental Program (UNEP) has been implemented in an effort to combat the release of selected persistent organic pollutants (POPs). POPs are found in environmental samples such as soils, sludges, solid and semisolid waste, and sediments. POPs are also found in biological samples such as human breast milk, and fish tissue. UNEP is interested in eliminating POPs from the environment because these compounds are considered toxic, carcinogenic, and mutagenic, and degrade slowly in the environment, posing a threat to the global environment. The following compounds are listed by UNEP to be POPS: • Pesticides: Aldrin, Chlordane, DDT, Dieldrin, Endrin, Heptachlor, Mirex, and Toxaphene • Industrial chemicals: Hexachlorobenzene (a type of BNA), and polychlorinated biphenyl (PCB) • Chemical by-products (Dioxins): Polychlorinated dibenzo-p-dioxins (PCDD) Accelerated Solvent Extraction (ASE) is equivalent to U.S. EPA Methods 3540, 3541, 3550, and 8151 for the extraction of organochlorine pesticides (OCPs), organophosphorous pesticides (OPPs), semivolatiles or base neutral acids (BNAs), chlorinated herbicides, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs). ASE complies with U.S. EPA Method 3545A for these compounds. ASE is an extraction technique that significantly streamlines sample preparation. This technique uses extraction solvents at elevated temperatures and pressure to increase the kinetics of the extraction process. The high pressure allows the solvent to be used above its boiling point, keeping it in a liquid state, and thus decreases the amount of time and solvent required to extract the desired analyte from the sample matrix. ASE replaces extraction techniques such as Soxhlet, sonication, and wrist-shaker with equivalent or better results. This application note describes methods and results for extraction of the POPs listed above, with tables comparing ASE to traditional extraction methods.