Improving Your Analysis by Treating Your Flow Path with Agilent’s NEW Ultra Inert Technology

Significance of the topic

The performance of gas chromatography–mass spectrometry (GC/MS) in trace analysis critically depends on the inertness of the flow path.
Active surfaces in the inlet, tubing, seals and fittings can adsorb or degrade analytes, compromising sensitivity, peak shape and data reliability.
Advances in flow path deactivation directly address these challenges and enable reliable detection at low concentration levels.

Objectives and study overview

This work evaluates Agilent’s new Ultra Inert flow path technologies for GC/MS labs performing trace analyses in environmental, food pesticide and forensic toxicology applications.
Key goals include:

• Improving sensitivity and reducing peak tailing for active compounds
• Enhancing linearity and reproducibility at low ppb–ppt levels
• Minimizing downtime and re-runs by stabilizing calibration over many injections

Methodology and instrumentation

Agilent developed two surface deactivation chemistries:

• Ultimetal Plus (inorganic vapor deposition) for metal parts and ferrules
• Ultra Inert (organic vapor deposition) for GC columns, liners and gold seals

Comparative tests used 7890/5975B and 7890B/5977 GC/MS systems configured with:

• J&W Ultra Inert GC columns (DB-5ms UI, DB-35ms UI, DB- UI 8270D)
• UI inlet liners (with and without glass wool)
• Flexible metal ferrules treated with UltiMetal Plus
• Ultra Inert gold seals
• UltiMetal Plus inlet weldments and transfer lines

Performance metrics included peak shape, response factors at multiple concentration levels (10–500 ng/mL), calibration linearity (R²), and response stability over 50+ injections.

Main results and discussion

• Peak shapes became markedly sharper, reducing tailing and improving resolution for sensitive pesticides and drugs of abuse.
• Average response factors increased by 10–50% across 26 pesticides using the Ultra Inert flow path versus standard hardware.
• Calibration curves for key compounds (e.g., acephate, omethoate) showed R² > 0.97 with the inert flow path versus < 0.60 for standard components.
• Reproducibility remained within tight limits over long sequences, with response factor drift minimized.
• Benefits extended to GC/MS/MS and high-resolution instruments, where chromatographic improvements complement mass-selective noise reduction.

Benefits and practical applications

The Ultra Inert flow path delivers:

• Enhanced sensitivity for trace-level active analytes
• Improved quantitation accuracy and linearity
• Reduced maintenance and fewer re-runs, boosting lab throughput
• Reliable performance for environmental, food safety and forensic testing

Future trends and potential applications

• Integration of inert flow path options on next-generation GC/MS platforms (e.g., 7890B/5977).
• Wider adoption in GC triple-quad, TOF and high-resolution systems to leverage both chromatographic and mass spectrometric selectivity.
• Expansion of sample preparation solutions (SPE, QuEChERS) to maintain system cleanliness and extend consumable lifetimes.
• Development of advanced purifiers and filter modules to control oxygen and moisture in carrier gas.

Conclusion

Maintaining an inert GC flow path is essential for reliable trace analysis of active analytes.
Agilent’s dual-chemistry approach and dedicated consumables (columns, liners, ferrules, seals, weldments) significantly improve sensitivity, linearity and stability.
The Ultra Inert flow path is recommended for high-confidence quantitative GC/MS and GC/MS/MS applications.

Used Instrumentation

• Agilent 7890B GC with Inert Flowpath option
• Agilent 5977B/5975B MS detectors
• J&W Ultra Inert GC columns (DB-5ms UI, DB-35ms UI, DB- UI 8270D)
• Ultra Inert inlet liners and gold seals
• UltiMetal Plus ferrules and inlet weldments
• Gas Clean GC/MS filters
• Agilent Bond Elut SPE and QuEChERS sample prep products