Organochlorine Pesticide Mix AB #2 Rtx®-CLPesticides and Rtx®-CLPesticides2 (0.25mm ID column set)

Significance of the Topic

Organochlorine pesticides remain widespread contaminants with significant environmental persistence and health hazards. Reliable analytical methods are essential for trace-level detection and quantification in environmental, food, and industrial quality control contexts.

Objectives and Study Overview

The application note details a gas chromatography method employing dual Rtx®-CLPesticides columns to achieve baseline separation of a standard mixture of 22 organochlorine pesticides and surrogate compounds. Key goals include demonstrating chromatographic resolution, sensitivity, and method robustness.

Methodology and Instrumentation

A 30 m × 0.25 mm ID Rtx®-CLPesticides column (0.25 μm film) and a 30 m × 0.25 mm ID Rtx®-CLPesticides2 column (0.20 μm film) are connected via a 5 m Siltek®-treated guard column and a Y Press-Tight® connector. Sample injection is 0.5 µL in splitless mode with a taper liner at 250 °C. The oven program ramps from 125 °C to 200 °C at 45 °C/min, to 230 °C at 12.5 °C/min, and then to 330 °C at 30 °C/min (2 min hold). Helium is used as carrier gas at constant linear velocity (41 cm/s at 125 °C). Detection is performed with an Agilent µ-electron capture detector at 330 °C.

Instrumentation Used

• Rtx®-CLPesticides 30 m, 0.25 mm ID, 0.25 µm (cat. # 11123)
• Rtx®-CLPesticides2 30 m, 0.25 mm ID, 0.20 µm (cat. # 11323)
• Rxi® guard column 5 m, 0.25 mm ID (cat. # 10029)
• Siltek®-treated Y Press-Tight® connector (cat. # 20486)
• Cyclo double taper liner, 2 mm (cat. # 20908)
• Agilent µ-ECD system

Main Results and Discussion

The method achieves complete separation of 22 target analytes, including BHC isomers, chlordane isomers, DDT and its metabolites, endosulfan isomers, endrin and derivatives, and surrogates. Chromatograms demonstrate sharp peaks with baseline resolution under 15 minutes. Dual-column configuration enhances selectivity and confirms peak identities across two stationary phases.

Benefits and Practical Applications

• High sensitivity and selectivity for trace-level organochlorine detection
• Robust, reproducible performance suitable for environmental monitoring, food safety, and QA/QC
• Inline guard column and Y-connector design minimize inertness and carryover
• Flexible temperature programming allows adaptation to similar analyte classes

Future Trends and Potential Applications

Advancements may include multidimensional GC, coupling with mass spectrometry for enhanced confirmation, rapid high-throughput methods, and eco-friendly carrier gases. Emerging stationary phases and microfluidic GC devices promise faster analysis and reduced solvent and gas consumption.

Conclusion

The described dual-column GC-ECD method using Rtx®-CLPesticides columns provides a reliable, high-resolution approach for the analysis of organochlorine pesticides. Its robustness and sensitivity make it a valuable tool for regulatory and research laboratories.

References

• Restek Corporation, Application Note GC_EV00940 and GC_EV00941: Organochlorine Pesticide Mix AB #2 Rtx®-CLPesticides and Rtx®-CLPesticides2.