New High Temperature PEG GC Column with Increased Temperature Limit and Ultra Low Bleed Level

Importance of the Topic

Gas chromatography analysis of industrial chemicals and complex matrices demands high thermal stability and reproducible retention times. Traditional polyethylene glycol (PEG) stationary phases are limited to 250–260°C, restricting late-eluting analytes and increasing column bleed at elevated temperatures. A high-temperature, ultra-low bleed WAX column enhances analytical performance and widens the scope of applications.

Objectives and Study Overview

• Evaluate thermal stability and retention time reproducibility of the new Agilent J&W DB-HeavyWAX versus conventional WAX columns.
• Assess column bleed behavior under prolonged high-temperature operation.
• Demonstrate applicability to challenging samples such as pyrolysis gasoline (PyGas).
• Verify selectivity similarity to established DB-Wax methods for seamless method transfer.

Methodology and Instrumentation

• Analyte: 100 ppm BTEX standard.
• Test columns: Agilent J&W DB-HeavyWAX (30 m x 0.25 mm x 0.25 µm) and two commercial WAX columns.
• Temperature program: isothermal until o-xylene elution, ramp to 280°C, 1-hour hold.
• Comparative runs: 50–100 hours at 280°C to measure retention time shift and bleed.
• PyGas sample analysis by ASTM D6563 on DB-HeavyWAX and DB-Wax columns.

Instrumentation Used

• Agilent 7890B GC with FID detector.
• Agilent 7693 autosampler.
• Helium carrier gas at constant flow (1–1.2 mL/min).
• Ultra Inert split inlet with glass wool liner.

Main Results and Discussion

The DB-HeavyWAX column maintained stable retention times for o-xylene over 50–100 hours at 280°C, while conventional WAX columns shifted by ~2 minutes. Bleed measurements showed the new column below 10 pA after extended use, compared to 50–60 pA for competitors. In PyGas analysis, raising the final temperature to 280–290°C enabled elution of late compounds without carryover, matching DB-Wax selectivity and simplifying method transfer.

Benefits and Practical Applications

• Extended upper temperature limit (up to 280–290°C) for late-eluting and heavy-matrix analytes.
• Enhanced retention time reproducibility over prolonged high-temperature runs.
• Ultra-low bleed improves sensitivity in GC and GC/MS workflows.
• Direct compatibility with existing DB-Wax methods—no retention time revalidation needed.

Future Trends and Potential Applications

Continued development of high-temperature polar phases for GC×GC applications as second-dimension columns. Integration into comprehensive two-dimensional GC systems for complex petrochemical samples. Exploration of further bleed reduction and stationary phase inertness to support trace-level analysis in environmental and food safety testing.

Conclusion

The Agilent J&W DB-HeavyWAX column combines extended thermal limits, exceptional retention time stability, and ultra-low bleed to address the challenges of high-temperature GC and GC/MS analyses. Its compatibility with established methods and suitability for demanding applications make it a valuable addition to industrial and research laboratories.

References

1. ASTM D2306 – Standard Test Method for C8 Aromatic Hydrocarbon Analysis by Gas Chromatography
2. ASTM D6563 – Standard Test Method for Benzene, Toluene, Xylene (BTX) Concentrates Analysis by Gas Chromatography