Inertness: What does it Mean for your Gas Phase Results?

Significance of the Topic

Maintaining inert surfaces throughout the gas chromatographic flow path is critical for accurate analysis of active compounds. Surface activity can lead to analyte adsorption, peak tailing, reduced sensitivity and poor quantitation. Laboratories handling complex matrices require highly inert liners, columns and transfer lines to ensure reliable performance at trace levels.

Objectives and Overview of the Study

This poster evaluates the inertness of an Ultra Inert flow path system under demanding conditions. Key goals are to compare standard and UI liners and columns, assess reproducibility over multiple injections, and demonstrate performance with challenging organophosphorus pesticides in olive oil.

Methodology and Instrumentation

The study employs a series of probe compounds and real-matrix pesticides to test activity. Standard forensic compounds and a QuEChERS olive oil extract spiked with six organophosphorus pesticides are injected repeatedly. Inertness is challenged by aggressive probe mixtures such as Grob’s mix.

Used Instrumentation

• GC System with three-way splitter to MSD and FPD
• Agilent 7890 GC and 5975C MSD
• Agilent J&W UI single tapered liner with wool
• DB-5ms UI and DB-35ms UI columns with deactivated fused silica transfer lines
• Splitless inlet at 250 °C
• MSD in SIM and scan modes; FPD with hydrogen and air flows

Main Results and Discussion

UI flow path components deliver narrow, Gaussian peaks and excellent reproducibility. With standard liners, peak shape deteriorates rapidly. In contrast, the UI liner and column combination maintains peak symmetry over 100 injections with relative standard deviations below 10 percent for all six pesticides, including methamidophos and acephate. The addition of an analyte protectant further enhances response stability for polar organophosphorus targets.

Benefits and Practical Applications

Implementing a fully inert flow path yields:

• Improved peak shape and sensitivity for active analytes
• Consistent quantitative performance over large sample batches
• Reduced maintenance, rework and recalibration frequency
• Higher throughput and confidence in trace-level results

Future Trends and Applications

Further development of inert coatings and liners will support ever more sensitive analyses in food safety, forensic toxicology and environmental monitoring. Integration with automated sample prep and protective additives promises robust workflows for complex matrices at sub-ppb levels.

Conclusion

Testing with aggressive probe mixtures confirms the superiority of Ultra Inert liners and columns for challenging analyses. A holistic inert flow path approach ensures reliable, reproducible data for active compounds, reduces downtime, and supports high-throughput trace-level workflows.

Reference

1. Jenkins W and Lynam K Addressing Concerns in QC Tests for GC Columns Agilent Technologies publication 5990-9961EN
2. Lynam K and Smith D Ultra Inert Wool Liner Performance Using an Agilent J&W DB-35ms UI Column with and without an Analyte Protectant for OP Pesticides Agilent Technologies publication 5990-8235EN