One Step Extraction, Cleanup and Direct to Vial Concentration for PCBs in Soil and Sediment

Introduction

Polychlorinated biphenyls are a class of organic compounds with 1 to 10 chlorine atoms attached to a pair of bonded benzene rings. PCBs were widely used for many applications, especially as dielectric fluids in transformers, capacitors, and coolants. Due to PCB’s toxicity and classification as a persistent organic pollutant, PCB production was banned by the United States Congress in 1979 and by the Stockholm Convention on Persistent Organic Pollutants in 2001.

PCBs have low water solubility and are largely chemically inert, making them extremely resistant to oxidation. These properties enable PCBs to with stand environmental degradation, and build up in soil and river sediment. These compounds are commonly detected using EPA Method 8082. This method determines the concentrations of various PCB congeners and Aroclors in extracts from solid and liquid matrices, including food products, using gas chromatography with electron capture detectors (ECD). This application provides a unique new option to speed up multiple sample prep processes into one. The FMS PLE (pressurized liquid extraction) system will automatically perform the extraction and sample cleanup using the FMS proprietary InCell column and deliver the extract for final concentration directly to a vial be injected directly by the GC system. This is a first for in the analysis of PCBs.

Instrumentation

• FMS, Inc. Power Prep PLE System
• FMS, Inc 5gm Acidic In-Cell Silica Column
• FMS, Inc. PowerVap Concentrator
• Thermo Fisher Scientific Polaris Q GCMS

Method Summary

PowerPrep PLE
1. Extraction solvent: Hexane/Methylene Chloride (50/50)
2. Extraction temperature: 120C
3. Extraction pressure: 1500 PSI
4. Extraction time: 15 minutes

PowerVap Concentrator
1. Pre-heat temp: 55 deg C
2. Pre-heat time: 15 minutes
3. Heat in Sensor mode: 65 deg C
4. Nitrogen Pressure: 15 PSI

Procedure
10 grams of are sample weighed out in 100ml beaker, repeated for 5 reps per matrix.

Samples were mixed & dried with Varian Hydro Matrix®

Dried sample transferred to a FMS extraction cell equipped with an InCell Acid Silica end cap.

Samples spiked with 1 ml (acetone) of a 1 ug/ml PCB congener solution.

The void cell volume filled with Ottawa Sand®, sealed and loaded on FMS PLE for extraction.

Sample Extracted and automatically transferred to FMS PowerVap Direct to Vial Concentrator

PowerVap Direct to Vial Concentrator

5 ul ISTD added to extract (PCB-209) & extract transferred to GC/MS for analysis.
 

Conclusions
The FMS PLE and Concentration system in combination with the FMS 5gm Acidic Silica gel In-Cell column is shown to automatically extract, clean-up and concentrate PCB samples at a high rate of speed producing excellent recoveries and reproducibility for both soil and sediment samples.

For more information contact FMS at:
FMS,Inc.
580 Pleasant Street
Watertown, MA 02472
Phone: 617-393-2396
Fax: 617-393-0194
Email: onlineinfo@fms-inc.com
www.fmsenvironmental.com