Robust GC Analysis of Volatile Amines on the Rtx-Volatile Amine Column

Importance of the Topic

Volatile amines play critical roles in industrial processes such as gas scrubbing to remove hydrogen sulfide and carbon dioxide during ammonia production. Accurate quantification of these basic, polar compounds is essential for process optimization, yet their strong interactions with active sites in the GC flow path often lead to peak tailing and poor reproducibility.

Objectives and Study Overview

This study evaluates the performance of the Rtx-Volatile Amine column for gas chromatographic analysis of volatile amines in challenging matrices, focusing on retention, selectivity, robustness against water injection, and reproducibility under harsh conditions.

Methodology and Instrumentation

• Column: Restek Rtx-Volatile Amine, 60 m × 0.32 mm ID fused silica capillary.
• Test Mix: Eight-component volatile amine mix (pyridine, 1,2-butanediol, nonane, diethylenetriamine, diethanolamine, 2-nonanol, 2,6-dimethylaniline, dodecane) prepared in methanol:dichloromethane (50:50).
• GC System: Agilent/HP 6890 with FID detector at 300 °C; helium carrier gas at 3.4 mL/min (linear velocity 44 cm/s at 160 °C).
• Oven Program: 160 °C hold 21 min ramped to 290 °C at 40 °C/min, hold 10 min.
• Injection: 1 µL split injection (17.8:1) with initial inlet temperature 250 °C and premium 4 mm single taper liner with wool.

Main Results and Discussion

The Rtx-Volatile Amine column demonstrated baseline resolution for all test components with sharp, symmetric peaks. It withstood over 600 water injections without loss of efficiency or changes in retention times, evidencing exceptional inertness and phase stability. Retention times ranged from approximately 5 to 22 minutes for the eight components, confirming good selectivity for both low- and high-boiling amines.

Benefits and Practical Applications

• Extended column lifetime under wet sample conditions reduces downtime and replacement costs.
• High inertness and reproducibility support accurate quantitation of volatile amines, including free ammonia, in quality control and process monitoring.
• Temperature stability to 290 °C enables analysis of amines up to C16 and periodic column bake-out for contaminant removal.

Future Trends and Potential Applications

Advancements may include further phase chemistries with enhanced selectivity for substituted amines, integration with mass spectrometric detectors for trace-level analysis, and application to environmental monitoring of amine-based solvents. The robustness of this column design may inspire similar approaches for other polar, reactive analyte classes.

Conclusion

The Rtx-Volatile Amine column offers a robust, inert, and selective solution for GC analysis of volatile amines in challenging matrices. Its ability to maintain performance after repeated water exposure and deliver reproducible, baseline-resolved peaks makes it a valuable tool for industrial and research laboratories.

References

Restek Corporation. Robust GC Analysis of Volatile Amines on the Rtx-Volatile Amine Column. Lit. Cat. PCSS2694A-UNV, 2018.