Increased thermal stability and maximum temperature of the Agilent J&W DB-HeavyWAX column

Significance of the Topic

Gas chromatography employing 100% polyethylene glycol (PEG) columns is critical for the sensitive, reproducible analysis of industrial chemicals, flavors, fragrances, and BTEX compounds. Extending the operating temperature enhances the ability to separate higher-boiling analytes without compromising phase stability or reproducibility.

Objectives and Study Overview

This application note compares the thermal stability and retention time reproducibility of the Agilent J&W DB-HeavyWAX column against conventional WAX phases. Using a BTEX mixture, the study assesses performance at final oven temperatures up to 280 °C over extended operation periods.

Methodology and Instrumentation

A BTEX standard (100 ppm each of benzene, toluene, ethylbenzene, o-xylene, p-xylene, m-xylene in methanol) was analyzed on three 30 m × 0.25 mm × 0.25 µm PEG columns: two commercial WAX phases and the DB-HeavyWAX. Chromatographic conditions included a split-mode inlet at 250 °C, helium carrier flow at 1 mL/min, and an oven program from 70 °C (10 min) ramped to 280 °C at 20 °C/min with a 60-min hold. Detection was performed by FID at 280 °C.

Main Results and Discussion

Conventional WAX columns, operated above their MAOT (250/260 °C), exhibited significant retention time drift when held at 280 °C, with shifts increasing from slight to pronounced after 50 hours. In contrast, the DB-HeavyWAX column maintained stable retention for all BTEX peaks even after 100 hours at 280 °C, showing only minimal shifts of a few seconds.

Benefits and Practical Applications

The extended temperature limit and enhanced thermal stability of the DB-HeavyWAX column allow reliable high-temperature separations of heavy industrial analytes without phase degradation. This translates into improved quantitation precision, longer column lifetimes, and the ability to develop faster or higher-temperature methods for QA/QC, environmental and petrochemical analysis.

Future Trends and Applications

Advances in stationary phase chemistry will continue to push temperature and chemical resistance, enabling simultaneous analysis of volatile and semi-volatile compounds in a single run. Integration with fast GC and high-throughput autosamplers may further boost productivity in industrial and environmental laboratories. Emerging applications in complex matrices, such as polymers and biofuels, will benefit from robust, high-temperature PEG phases.

Conclusion

The Agilent J&W DB-HeavyWAX column delivers a reliable increase in maximum operating temperature to 280/290 °C while preserving retention time stability over extended use. This performance surpasses traditional WAX phases and broadens the analytical scope for challenging industrial and environmental applications.

Reference

• ASTM D2306. Standard Test Method for C8 Aromatic Hydrocarbon Analysis by Gas Chromatography.
• ASTM D6563. Standard Test Method for Benzene, Toluene, Xylene (BTX) Concentrates Analysis by Gas Chromatography.
• Reese A.; Vickers A.; George C. GC Column Bleed: A MASS PerSPECtive. Agilent Technologies, publication B-0442, 2001.