Automated One Step Solid Phase Extraction (SPE) and Concentration of Organochlorine Pesticides in Water

Organochlorine pesticides are man-made organic chemicals with a history of wide spread use in the United States, as well as globally. Tending to be very persistent in the environment, they have made their way into sediments and drinking water supplies posing serious health risks. Many organochlorines are suspected endocrine disruptors.

Traditional extraction of organochlorine pesticides involves a liquid/liquid extraction via sep-funnel. This manual technique is time consuming and uses a large volume of chlorinated solvent making it both costly and often generating poor results. The use of Automated One Step SPE Direct to Vial Concentration allows for the most rapid, reproducible extractions with minimal use of solvents.

Instrumentation

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

• FMS, Inc. PowerVap Concentrator

• FMS, Direct to Vial Concentrator tubes

• 1 g Waters Sep-Pack tC18 cartridges

• Agilent 7890A GC with uECD

PowerPrep SPE

1. C18 Cartridge conditioned with 10 mL Methanol

2. C18 Cartridge conditioned with 10 mL DI H₂O

3. Sample loaded across C18 Cartridge via vacuum

4. Sample bottle auto rinsed and rinse loaded on C18

5. C18 cartridge dried with Nitrogen

6. Cartridge eluted with methylene chloride

PowerVap Concentrator

1. Pre-heat temp: 65 °C

2. Pre-heat time: 30 min

3. Heat in Sensor mode: 65 °C

4. Nitrogen pressure: 15 PSI

Procedure

Sample Prep and Extraction

1. Five, 1 L water samples spiked with 1 mL EPA 8081 surrogate spiking solution (2 analytes).

2. Samples spiked with EPA 8081 pesticide spiking solution (20 analytes).

3. Program is initiated to run each sample sequentially.

4. Samples are extracted and automatically transferred to FMS PowerVap Concentrator w/direct to vial tubes.

5. Extracts are concentrated with PowerVap Directly to a GC vial to 1 mL, exchanged to Hexane (15 mL) and re-concentrated to a final volume of 1 mL.

6. Extract is removed from PowerVap the vial is capped and transferred to Agilent GC for analysis.

Table 1

Conclusions

The results of five water samples indicate the FMS Power Prep Automated One Step SPE Direct to Vial Concentration is capable of delivering accurate results and recoveries of analytes in water samples with a high rate of reproducibility. This proves to be enormously superior to traditional liquid/liquid extractions that are time consuming, inconsistent, and costly in terms of reagents and time management. The addition of the FMS PowerVap equipped with direct to vial tubes eliminates the need to transfer samples, enabling samples to go directly from sample bottles to GC vials in a single extraction process.

FMS, Inc.

580 Pleasant Street, Watertown, MA 02472

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

Website: www.fmsenvironmental.com