Automated Column Chromatography Cleanup with Reduced Solvent Volume in POPs Analysis Including all 209 PCBs

New Organic Monitoring Techniques
Oral Presentation

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


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

ABSTRACT

Labor and solvent use in sample cleanup for environmental analysis of Persistent Organic Pollutants (POPs), such as polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs), and biphenyls (PCBs), are important factors that determine sample throughput and business-cost.

Manual techniques used in cleanup have historically involved large amounts of solvents and have been multiple day processes, with sample concentration steps after each column. Here we present a recently developed automated system with a multi-pump and a sample processing unit using a method that has been optimized for low solvent volume.

The automated system can be used to process up to six samples in parallel and is fast (30 - 45 min); a closed system with low chance of cross-contamination; use of certified pre-packaged columns with no native background; low energy cost (multi-pump only); and choice of various column kits (size of acid silica column varies depending on amount of lipid in sample). It uses two columns: acidified silica (fat removal capacity 0.15-7 g) and alumina. The columns are stacked on top of each other to form a column assembly. Solvents used are hexane, 10% dichloromethane-hexane, and dichloromethane.

The system runs samples with all 209 PCBs collected with 55 mL hexane and dichloromethane and excellent recoveries (13C labeled > 75%). The advantage is that the samples can contain considerable amounts of dichloromethane (~ 7 mLs), eliminating the need for solvent-exchange to hexane during blow-down prior to cleanup.

For combined PCDD/F and PCBs analysis, extracts in toluene can be processed without carbon column and total volume use of ~ 100 mLs, also collecting all 209 PCBs. 13C PCDD/F and 13C PCB recoveries were all > 75%.

The low amounts of solvent needed for these newly developed methods reduce sample concentration times prior to analysis and solvent cost, also leading to less time involved from lab technicians.