Speed Up Multiresidue Pesticides Analysis in Food with Low-Pressure GC-MS

Importance of the Topic

Multiresidue pesticide analysis is essential for ensuring food safety and meeting regulatory requirements. Traditional GC-MS methods can be time-consuming and may struggle with high sample loads and rapid turnarounds. Implementing faster chromatographic techniques without expensive hardware upgrades can significantly enhance lab productivity.

Objectives and Study Overview

This study evaluates a low-pressure GC-MS (LPGC-MS) approach for rapid multiresidue pesticide screening in strawberry samples. The goal is to compare performance against conventional GC methods, assessing analysis speed, resolution, and applicability to routine food safety testing.

Methodology and Instrumentation

A factory-assembled LPGC column kit from Restek featuring:

• 5 m × 0.18 mm ID restrictor column
• 15 m × 0.53 mm ID, 1 µm film Rtx-5ms analytical column with 1 m integrated transfer line

Chromatographic conditions:

• Carrier gas: Helium at 2 mL/min constant flow
• Oven program: 80 °C (1 min), ramp 35 °C/min to 320 °C, hold 5 min
• Injection: 1 µL splitless with 0.5 min hold; inlet liner: Topaz single taper with wool

MS detection on a Thermo Scientific TSQ 8000 triple quadrupole GC-MS operating in SIM mode (35–550 m/z).
Sample preparation followed QuEChERS EN 15662 extraction with MgSO₄/PSA dSPE cleanup and internal standards at 20 ppb.

Main Results and Discussion

• All 209 target pesticides eluted within 8.33 min vs. 26.34 min on a conventional 30 m column, achieving a 3× speed increase.
• Peak shapes were narrow and tall, improving sensitivity despite reduced plate count and resolution.
• Mass spectrometric selectivity compensated for most coelutions, though isobaric pairs (e.g., 4,4′-DDD/2,4′-DDT) require further chromatographic separation if critical.
• Cis/trans isomers (permethrin) and isomer clusters (cyfluthrin/cypermethrin) remained quantifiable under SIM conditions.

Benefits and Practical Applications

• Significant throughput gains for high-volume food safety labs without major capital investment.
• Simple implementation via column swap and method update, with robust, leak-tested connectors.
• Reduced background noise and stabilization times due to integrated transfer line design.
• Compatibility with existing GC-MS and GC-MS/MS systems and conventional carrier gases.

Future Trends and Opportunities

Potential advancements include:

• Expanded use of LPGC-MS in diverse food matrices and regulatory settings.
• Integration with high-throughput automation and data analytics tools.
• Development of optimized low-pressure column chemistries for enhanced separation.
• Advances in GC-MS interface design to further reduce cycle times.

Conclusion

Low-pressure GC-MS using a factory-assembled column kit delivers rapid, robust multiresidue pesticide analysis in strawberries with a threefold reduction in run time. The approach is accessible, cost-effective, and well-suited for modern food safety laboratories seeking to increase throughput without sacrificing data quality.

Reference

Restek Low-Pressure GC Column Kit; Thermo Scientific TSQ 8000 Triple Quadrupole GC-MS.