Organochlorine Pesticides by EPA Method 8081B on Rtx®-CLPesticides/Rtx®-CLPesticides2 (extended list)

Significance of the topic

Organochlorine pesticides are widely regulated due to their persistence, bioaccumulation potential and toxicity. Reliable analytical methods are essential for environmental monitoring, food safety and regulatory compliance. The described approach using EPA Method 8081B on specialized GC columns provides robust separation and sensitive detection of an extended suite of these compounds.

Objectives and study overview

This work aims to demonstrate the performance of two Restek Rtx®-CLPesticides columns (with Rtx®-CLPesticides2 phase) paired via a guard column and a micro-electron capture detector (micro-ECD) for the analysis of 38 organochlorine pesticides. The focus is on chromatographic resolution, method speed and detection sensitivity under the conditions of EPA Method 8081B.

Methodology and Used instrumentation

The analytical system consists of:

• Gas chromatograph: Agilent/HP 6890 GC with splitless injection (1 µL, 250 °C, 0.3 min hold)
• Columns: Rtx®-CLPesticides2 (30 m × 0.32 mm ID, 0.25 µm) and Rtx®-CLPesticides (30 m × 0.32 mm, 0.32 µm) connected via a 5 m deactivated guard column with Y Press-Tight® connector
• Carrier gas: Helium, constant flow at 28 cm/s
• Oven temperature program: 80 °C (initial), ramp to 175 °C at 8 °C/min, to 195 °C at 11 °C/min, to 235 °C at 7 °C/min, then to 320 °C at 25 °C/min (3 min hold)
• Detector: Micro-ECD at 330 °C, makeup gas N₂ at 60 mL/min
• Calibration: Multicomponent pesticide mixes in hexane, concentrations ranging from 40 ng/mL to 500 ng/mL

Main findings and discussion

The method achieved baseline separation for 38 organochlorine pesticides, including isomeric BHCs, chlordane congeners, DDT/DDD/DDE isomers and cyclodienes, in a single 43-minute run. Calibration concentrations covered 40–500 ng/mL, demonstrating the detector’s sensitivity for trace-level quantitation. The dual-column arrangement enhanced peak shape and resolution for challenging compounds such as cis- and trans-chlordane.

Benefits and practical applications

• High resolution and sensitivity enable compliance monitoring for drinking water, soil and food commodities.
• Extended analyte list broadens scope for comprehensive environmental screening.
• Method robustness suits routine QA/QC laboratories requiring reproducibility and regulatory alignment.

Future trends and applications

Advances may include coupling with mass spectrometric detectors for confirmation, miniaturized or portable GC systems for field analysis, and automated sample preparation to increase throughput. Integration with data analytics and machine learning could further enhance method performance and result interpretation.

Conclusion

The EPA 8081B method on Rtx®-CLPesticides columns with micro-ECD offers a validated, sensitive and efficient approach for the analysis of a broad range of organochlorine pesticides. Its demonstrated performance supports its use in regulatory, environmental and food safety laboratories.

References

• U.S. EPA. Method 8081B: Organochlorine Pesticides by Gas Chromatography. 2007.
• Restek Corporation. Application Note GC_EV1193: Organochlorine Pesticides on Rtx®-CLPesticides Columns.