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Extraction of Polychlorinated Biphenyls from Polyurethane Foam Filters

November 4, 2019
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Summary


The EDGE® offers a reliable, quick, and efficient sample preparation method for any sample type, including the extraction of polychlorinated biphenyls (PCBs) from polyurethane foam (PUF) filters. It utilizes a combination of pressurized fluid extraction and dispersive solid-phase extraction to drastically reduce the sample preparation time, solvent usage, and potential for human error by unprecedented levels. EDGE recovery results are comparable to the traditional extraction method, Soxhlet, for the small and large PUF filters. The extractions performed with the EDGE use less solvent, last seven minutes, and do not require post extraction clean-up or volume transfer. The Soxhlet extraction apparatus took 16 hours, 300 mL of solvent, and multiple vessel transfers, further highlighting the extraction efficiency of the EDGE.

 

Introduction


In this application note, the EDGE is compared to Soxhlet extraction as a method for the extraction of PCBs from PUF filters. The U.S. EPA TO-4A Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air refers to Soxhlet extraction as the primary extraction method used to accurately quantify PCBs extracted from Polyurethane foam (PUF) filters. PUF is the primary material used to filter and capture persistent organic pollutants (POPs), including PCBs for air monitoring, as described in US EPA TO-4A. PUF filters are used in high-volume air sampling systems, or as passive air samplers (PAS), because of their ability to trap PCBs. As a PAS, PUF filters are economical and do not require electricity, like high-volume air samplers.


The importance of monitoring ambient air for PCBs is related to their negative impact on human health and the environment. PCBs are man-made chlorinated organic compounds containing a biphenyl nucleus on which a combination of one to all ten of the hydrogen atoms are substituted with chlorine. Their use was very popular in the electronics and automotive industries, until the US EPA banned them in 1979. Because of their chemical and physical stability, PCBs do not regularly break down in the environment and are, therefore, still present in soil, air, and water sources. Inhalation of PCBs is connected to a variety of adverse health effects, including cancer. Risk of inhalation exposure is greater in industrial and urban areas, where PCB-contaminated equipment is likely still present. The volatilization of PCBs from spills, landfills, road oils, and other sources, results in measurable atmospheric emissions. Atmospheric transport is the primary mode of the global distribution of PCBs. This further highlights the importance of monitoring the presence of PCBs in ambient air and extracting them for accurate quantification at variable concentrations of contamination.


The efficiencies for the extraction of PCBs from PUF filters obtained with the EDGE are comparable to Soxhlet extraction. A typical Soxhlet extraction takes 16 hours, up to 300 mL of solvent and multiple vessel transfers. In contrast, extraction on the EDGE takes seven minutes, uses less than 50 mL of solvent, and does not require a vessel transfer.

 

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