Analysis of Hexamethylenediamine

Importance of the Topic

Underivatized aliphatic amines such as hexamethylenediamine are widely used as intermediates in polyurethane, nylon and specialty polymer production. Their purity and concentration directly impact product quality, process efficiency and safety. Rapid and reliable analysis of these basic compounds is therefore critical for both industrial quality control and environmental monitoring.

Study Objectives and Overview

This application note evaluates a gas chromatographic method for the direct analysis of hexamethylenediamine and related primary and secondary amines using a polar capillary column and flame ionization detection. The goal is to demonstrate baseline separation of a mixture of twelve underivatized amines, illustrating method robustness and suitability for routine laboratory workflows.

Methodology and Instrumentation

This study employed a Shimadzu gas chromatograph equipped with a flame ionization detector (FID) and an SH-PolarX capillary column. Key operating parameters included:

• Column: SH-PolarX, 30 m × 0.53 mm I.D., 0.50 μm film thickness
• Oven program: 95 °C (1 min), ramp at 7 °C/min to 235 °C, hold 2 min
• Injection: 0.2 µL direct injection of a neat sample onto a Restek Uniliner® liner, split ratio 1:10
• Carrier gas: Hydrogen at 40 cm/s (approx. 5 mL/min)
• Injector/detector temperatures: 255 °C
• Detector: FID with a sensitivity of 64 × 10⁻¹¹ A/FS

This setup enabled direct analysis without chemical derivatization, simplifying sample preparation and reducing analysis time.

Main Results and Discussion

The method achieved clear separation of twelve test compounds—ranging from cyclohexane to hexamethylenetriamine derivatives—with sharp, symmetric peaks and no detectable carryover. Retention times increased with molecular weight and polarity, confirming the column’s ability to resolve structurally similar amines. The direct injection approach produced reproducible peak areas and retention times, suitable for quantitative analysis at concentrations of 50 µg/mL.

Benefits and Practical Applications

This GC-FID method offers several advantages for analytical and quality control laboratories:

• No derivatization required, minimizing sample handling and reagent costs
• Short analysis time with high peak resolution among basic compounds
• Robustness for routine monitoring of polymer intermediates and environmental samples
• Compatibility with aqueous amine solutions and neat samples

Future Trends and Potential Applications

Emerging directions include coupling polar columns with mass spectrometry to enhance selectivity and sensitivity, exploring faster temperature programming for high-throughput screening, and adapting the method for volatile impurity profiling in complex matrices. Development of microbore or multiplexed column systems could further reduce solvent and carrier gas consumption.

Conclusion

The direct GC-FID method on an SH-PolarX column provides a straightforward, reliable approach for the separation and quantification of hexamethylenediamine and related amines. Its simplicity and performance make it well suited for industrial quality control and research laboratories seeking efficient analysis of unmodified basic compounds.

References

No external literature references were provided in the original application note.