Analysis of Lambda-Cyhalothrin using the AT-Column Concentrating Technique

Significance of the topic

The concentration of trace pesticide residues such as lambda-cyhalothrin in oily crop extracts is critical for food safety and regulatory compliance. Traditional GC-MS injections can suffer from matrix interference and low sensitivity when analyzing large sample volumes. The AT-Column concentrating technique offers direct transfer of analytes onto the capillary column head under cooled conditions, enhancing sensitivity and reducing method development time.

Study objectives and overview

This application note presents a method replacing an existing LC-MS protocol for detecting low levels of lambda-cyhalothrin in hexane extracts of oily crops. The main aim is to demonstrate the AT-Column technique’s ability to concentrate analytes directly, minimizing solvent load and injection optimization.

Methodology and instrumentation

The AT-Column concentrating injection technique involves injecting a large solvent volume under controlled temperature and gas pressure. Solvent vapor is vented while analytes are trapped in the liner and subsequently transferred to the column head when the GC oven program begins.

• Injector: ATAS Optic 2-200 programmable injector with AT-Column kit
• Gas chromatograph: HP5890 coupled to HP5971 mass selective detector
• GC column: HP5-MS, 30 m × 0.25 mm i.d., 0.50 μm film thickness

Main results and discussion

The generated chromatogram showed clear separation of lambda-cyhalothrin with high signal-to-noise ratio at trace levels. The large-volume injection (30–100 μL) under split vent mode allowed efficient solvent removal and analyte focusing. The method achieved reproducible retention times and consistent peak areas across multiple injections, indicating robust performance in complex oily matrices.

Benefits and practical applications

• Enhanced sensitivity for trace pesticide residues
• Reduced sample preparation and method optimization
• Efficient solvent venting and analyte focusing
• Direct compatibility with standard GC-MS systems

Future trends and applications

The AT-Column concentrating technique can be extended to other semi-volatile organic compounds in diverse matrices. Future developments may integrate automated injection-to-analysis workflows, coupling with high-resolution mass spectrometry for greater selectivity, and expanding application in environmental and food safety laboratories.

Conclusion

The AT-Column concentrating injection method provides a reliable and sensitive approach for analyzing lambda-cyhalothrin residues in oily crop extracts. It streamlines the analytical workflow by combining large-volume injection with efficient solvent removal, reducing method development time while maintaining robust performance.

Reference

• Derek Brown, Agrisearch (permission to publish)
• Alan Tuckley, Agilent Technologies (column provision)