Performance and Durability for High-Temperature GC - Agilent J&W high-temperature GC columns and consumables

Significance of the Topic

High-temperature gas chromatography (HT-GC) extends conventional GC into temperature ranges up to 450 °C and above, enabling the separation and analysis of high-boiling compounds such as heavy petroleum cuts, biodiesel components, waxes, polymers, surfactants, and specialty food lipids. Reliable HT-GC methods are essential for simulated distillation, quality control in refining, polymer additive profiling, and advanced research.

Objectives and Study Overview

This article evaluates the performance and durability of Agilent J&W high-temperature GC columns and related consumables under extended high-temperature operation. It compares polyimide-coated fused silica columns (DB-1ht, DB-5ht, VF-5ht, DB-17ht) and deactivated stainless steel columns (UltiMetal, ProSteel) against competitive offerings. Key goals include assessing column stability, bleed levels, peak shape, and lifetime at 360–450 °C across representative applications.

Methodology and Instrumentation

Columns were conditioned at constant 400 °C for durations up to 120 h. Performance was tracked by theoretical plates/meter, baseline stability, and peak tailing on test mixtures (alkanes, alcohols, phenolics, polywax standards, beeswax hydrocarbons, Fischer–Tropsch products). Consumables optimized for HT-GC—BTO septa, graphite and Ultra Inert ferrules, high-temperature liners—were employed to minimize leaks and oxygen contamination. Agilent 7890B GC systems with FID detectors, MMI splitless, programmable temperature vaporizing (PTV), and cool on-column inlets were used, with helium or hydrogen carrier gases.

• Fused silica columns: DB-5ht, DB-1ht, VF-5ht, DB-17ht, DB-HT Sim Dis
• Stainless steel columns: UltiMetal VF-5, ProSteel DB-HT Sim Dis
• Instrumentation: Agilent 7890B GC / FID, MMI, PTV, cool on-column inlets
• Consumables: BTO septa, graphite seals, Ultra Inert liners, UltiMetal Plus ferrules
• Applications: Simulated distillation, polywax analysis, bee wax hydrocarbon profiling, Fischer–Tropsch product separation

Main Results and Discussion

Polyimide-coated DB-5ht columns maintained their coating integrity and theoretical plates after 25 h at 400 °C; competitor columns exhibited flaking and phase breakdown. Over 120 h, Agilent columns retained >90 % of initial efficiency and showed no peak tailing, whereas competitor columns lost >50 % efficiency and displayed significant tailing. Stainless steel UltiMetal columns operated leak-free at 430–450 °C, delivering efficiency comparable to fused silica with very low bleed and stable baselines in polywax and wax separations. Application examples demonstrated reliable distillation range to C120+, high-resolution profiling of beeswax alkanes up to C52, and separation of Fischer–Tropsch hydrocarbons to C90+ at 440 °C.

Benefits and Practical Applications

• Extended lifetime of GC columns at 360–450 °C with minimal bleed
• Improved peak shape and low baseline noise for high-boiling analytes
• Robust analysis of petroleum cuts, biodiesel, waxes, surfactants, food and polymer additives
• Flexible choice of fused silica tubing (≤400 °C) or stainless steel (up to 450 °C) for extreme applications
• High-temperature consumables reduce leaks, oxygen ingress, and outgassing

Future Trends and Possibilities

Continued development of stationary phase chemistries and column materials may extend HT-GC to >450 °C, enabling deeper profiling of heavy bio-oils and advanced petrochemical fractions. Integration of automated leak detection, inert flow paths, and AI-driven method optimization will further enhance reproducibility and lab productivity. Emerging applications include real-time monitoring of polymerization reactions and advanced GC-MS coupling under extreme temperature regimes.

Conclusion

Agilent J&W high-temperature GC columns and consumables outperform competitive products in durability, inertness, and chromatographic stability at elevated temperatures. Their optimized polyimide coatings and deactivated stainless steel designs minimize bleed, maintain column integrity, and extend operational lifetimes, supporting a wide range of high-boiling compound analyses in research and industrial laboratories.

Reference

• Agilent Technologies. Application Note 5994-1013EN: Defining GC column temperature limits and lifetime evaluations.