The importance of Agilent's inertness for columns, consumables and hardware

Importance of Topic

In gas chromatography and GC/MS, surface activity within the flowpath can cause broad or missing peaks, unstable baselines and poor sensitivity—especially for trace-level analyses of active or polar compounds. Inertness from the injection port through the column and detector is essential for reliable quantitation, low detection limits and consistent chromatography in environmental, forensic, pharmaceutical and petrochemical laboratories.

Objectives and Overview

This study reviews Agilent’s end-to-end inert flowpath solution, combining two proprietary deactivation chemistries—UltraInert and UltiMetal-Plus—to treat liners, seals, columns, ferrules, unions, transfer lines and inlet weldments. The goal is to demonstrate how a fully inert GC/GC-MS system improves peak shape, response and reproducibility for challenging analytes.

Methodology and Instrumentation

The approach employs:

• UltraInert deactivation on glass, steel, gold and silica surfaces.
• UltiMetal-Plus treatment on metal ferrules, unions, transfer lines and inlet shells.
• Systematic QC testing with test probe mixtures (acidic, basic, alcohol and non-active probes) at nanogram levels to verify column and liner inertness.
• Comparative experiments on Agilent 7890 GC and 5975/5977 MS, using standard and UltraInert consumables, DB-5ms UI and DB-624 UI columns, UltraInert liners, gold seals and flexible metal ferrules.

Main Results and Discussion

• Columns and liners treated with UltraInert chemistry produced narrow, symmetric peaks for active probes, while untreated systems showed tailing, signal loss or extra artefacts.
• Grob-type and DB-5ms test mixtures at trace levels revealed that UltraInert columns maintained linearity and peak height even for acids and bases that adsorb on active sites.
• The UltraInert test probe mixture allowed clear differentiation between high-performance and mediocre columns.
• UltiMetal-Plus ferrules and unions eliminated adsorption on metal surfaces, preserving pesticide and drug-of-abuse responses at ppb levels.
• UltraInert inlet liners with glass wool gave consistent low breakdown of sensitive analytes (e.g. endrin) over hundreds of injections, outperforming competitor liners.

Benefits and Practical Applications

• Improved detection limits and signal-to-noise ratios for polar and labile compounds.
• Enhanced peak shape and reproducibility across split/splitless injections for trace environmental and forensic samples.
• Longer maintenance intervals due to reduced analyte adsorption and carry-over.
• Seamless integration into existing methods without changing column selectivity or retention indices.
• Simplified compliance documentation via individual column performance certificates.

Future Trends and Opportunities

Looking ahead, full inertness solutions will extend to micro- and nano-flow systems, high-temperature polymers and automated workflows. Next-generation probe mixtures, real-time QC monitoring and digital traceability of consumable performance will further enhance robustness for ultratrace analyses in metabolomics, clinical diagnostics and environmental monitoring.

Conclusion

Comprehensive inert flowpath components—from injection liners and ferrules to columns and detector connections—deliver significant gains in sensitivity, peak quality and reliability. Agilent’s UltraInert and UltiMetal-Plus technologies provide a turnkey solution for demanding GC and GC/MS applications, reducing system artefacts and boosting laboratory productivity.

Instrumentation

• Agilent 7890B GC with inert flowpath option
• Agilent 5975/5977 MSD
• DB-5ms UltraInert and DB-624 UltraInert GC columns
• UltraInert single-taper liners with glass wool
• UltraInert gold inlet seals
• UltiMetal-Plus flexible metal ferrules, unions and transfer lines
• Agilent 7683B autosampler with 0.5 µL syringe for split injections