Automated One Step Solid Phase Extraction and Concentration of PCBs in Water

PCBs are a group of synthetic organic chemicals that contain 209 individual compounds (known as congeners) with varying harmful effects. PCBs enter the environment as mixtures containing a variety of individual components. PCBs have been widely used as coolants and lubricants in transformers, capacitors, and other electrical equipment. The manufacture of PCBs stopped due to evidence that PCBs build up in the environment and cause harmful effects. Due their extreme toxicity, durability, and wide industrial use, PCBs have found their way into drinking water supplies. The PowerPrep SPE and PowerVap Direct to Vial Concentration system speeds up the sample prep process for the analysis of PCBs by combining these sample prep steps into one.

Table I: Results

Instrumentation

• FMS, Inc. Power Prep SPE (solid phase extraction) system

• Waters Oasis 1 g HLB SPE cartridge

• FMS, Inc. PowerVap Concentrator

• Thermo Fisher Scientific Polaris Q GCMS

Method Summary

PowerPrep SPE

1. Condition Cartridge: 10 mL MeOH

2. Condition Cartridge: 10 mL H₂O

3. Load Sample: 15 min

4. Rinse bottle: 5 s

5. Load rinse: 1 min

6. Dry Cartridge: 30 min

7. Elute Sample: 20 mL DCM

PowerVap Concentrator

1. Pre-heat temp: 55 °C

2. Pre-heat time: 30 min

3. Heat in Sensor mode: 65 °C

4. Nitrogen Pressure: 15 PSI

Figure 1: Results of PCB congeners in sample extract.

Procedure

Five 1 L water samples were each spiked with a mixture of 19 individual PCB congeners at 1 ug/mL each. Samples were also spiked with a 1 ug/mL tetrachloro-m-xylene solution as an extraction surrogate. Using the Power Prep SPE system, samples were then loaded on prewet Oasis HLB cartridges using vacuum to draw the samples across the cartridge. Sample bottles were automatically rinsed. Cartridges were dried using a nitrogen stream blown across the cartridge to remove all remaining water. Once dried, the cartridges were eluted with 20 mLs of DCM directly to the FMS PowerVap Concentrator into direct to vial tubes. Extracts were blown down to a 1 mL final volume using the FMS direct to vial concentrator tubes. Extracts were then transferred for GC–MS analysis.

Conclusions

The FMS PowerPrep SPE and PowerVap perform Automated One Step and Direct to Vial Concentration. Combining sample prep processes is shown to efficiently extract PCB samples at a high rate of speed producing excellent recoveries and reproducibility for water samples. The combination of the FMS PowerPrep SPE system and the Waters Oasis HLB cartridge demonstrates consistent, reproducible, reliable high throughput automated sample extraction of PCBs.

FMS, Inc.

580 Pleasant Street Watertown, MA 02472

tel. (617) 393-2396, fax: (617) 393-0194

Email: onlineinfo@fms-inc.com

Website: www.fmsenvironmental.com