Automated Sample Processing of POPs with No Dichloromethane and Low Volume Solvent Use

New Organic Monitoring Techniques
Oral Presentation

Prepared by R. Addink, T. Hall
Fluid Management Systems, 900 Technology Park Dr, Billerica, MA, 01821, United States


Contact Information: [email protected]; 617-393-2396

ABSTRACT

Persistent organic pollutants (POPs) such as polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs) and biphenyls (PCBs) continue to attract interest around the world due to strict regulations in force in many countries. Rapid extraction, sample clean up, and analysis are therefore needed for many laboratories processing samples for POPs.

An automated cleanup system was developed, which allows for fast cleanup (60 min or less). Solvent consumption is limited to 120-270 mLs and no dichloromethane is used during the cleanup. This fully automated system allows for sample turnaround times of only a few hours and same day analysis and results.
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The system uses pre-packaged, certified acidified silica, carbon and alumina columns (in that order). It uses hexane and toluene for the sample cleanup and elution. Columns are conditioned with hexane, followed by sample loading (in hexane). The silica columns are then eluted with hexane, bringing the PCDD/Fs and PCBs onto the carbon and alumina columns. The carbon columns are then eluted with toluene, collecting PCDD/Fs and co-planary PCBs (Fraction # 1), followed by toluene elution of the alumina columns, collecting mono- and di-ortho PCBs (Fraction # 2). Fully automated evaporation typically at 55-60 oC with Direct-to-Vial Connections allows for fast volume reduction and eliminates the need of sample transfer to vial.

Samples containing up to 5 g fat can be easily processed with this method with the system allowing for running up to 8 samples in parallel. Samples tested included fatty acids, feed, fish oils, and sediment. Recoveries of 70-110 % were obtained for all PCDD/Fs and WHO-12 and indicator PCBs. Absence of dichloromethane in the cleanup is important as many laboratories around the world are phasing out this solvent. The system is easily operated and programmed with a built-in computer which allows unattended cleanup runs and fast, same-day results.