Analysis of Amines (low MW)

Importance of the Topic

Low molecular weight alkylamines are critical analytes in environmental monitoring, food safety, pharmaceutical quality control and petrochemical process analysis. Their high volatility, polarity and basic character challenge chromatographic separation and quantitation. Robust methods for fast, reproducible analysis of these compounds support regulatory compliance, process optimization and research into amine-related reactions and emissions.

Objectives and Study Overview

This application note evaluates the performance of a base-deactivated SH-PolarX GC column for direct analysis of nine low molecular weight amines. The goals include:

• Assessing the ability to resolve primary and secondary alkylamines without derivatization
• Demonstrating repeatability and sensitivity under isothermal conditions
• Establishing a rapid protocol suitable for routine laboratory use

Methodology

A direct injection gas chromatographic method was developed under the following conditions: 1 μL sample volume, injector temperature 250 °C, detector (FID) temperature 250 °C and isothermal column temperature of 45 °C. Hydrogen served as the carrier gas at 5 mL/min, corresponding to 40 cm/s linear velocity. The method was designed for straightforward operation with minimal sample preparation.

Used Instrumentation

• Gas chromatograph with FID detector
• Column: SH-PolarX, 30 m × 0.53 mm I.D., 1.00 µm film thickness (P/N 227-36300-01)
• Carrier gas: H₂ at 5 mL/min (linear velocity 40 cm/s)
• Injection: direct 1 µL, splitless
• Injector and detector temperatures: 250 °C
• Column temperature: isothermal 45 °C

Main Results and Discussion

The SH-PolarX column achieved baseline separation of nine amines: trimethylamine, dimethylamine, ethylamine, methylamine, isopropylamine, n-propylamine, tert-butylamine, diethylamine and sec-butylamine. Peaks were sharp and well resolved under isothermal conditions, demonstrating the column’s high inertness and selective polarity. The method provided consistent retention times and good peak symmetry, facilitating reliable identification and quantitation by FID.

Benefits and Practical Applications

• No derivatization step reduces sample preparation time and potential errors
• Isothermal operation simplifies method transfer and instrument calibration
• High reproducibility supports quality control in environmental, food and pharmaceutical laboratories
• Fast analysis enhances sample throughput in routine workflows

Future Trends and Applications

Advances may include coupling SH-PolarX with mass spectrometric detection for unequivocal identification, implementation in automated high-throughput platforms, and adaptation to microfluidic or portable GC systems for field monitoring of volatile amines. Continued column deactivation improvements and novel stationary phases could further enhance separation of highly polar or reactive amines.

Conclusion

The SH-PolarX base-deactivated GC column provides a simple, reliable and fast approach for direct analysis of low molecular weight alkylamines. Its high selectivity and inertness enable baseline separation of nine common amines under isothermal conditions, making it an excellent choice for routine laboratories focused on environmental analysis, quality control and process monitoring.