Analysis of Amines/Alcohols/Chlorides

Significance of the topic

Long-chain aliphatic amines, alcohols and chlorides serve as key intermediates and active agents in surfactants, detergents, pharmaceuticals and polymer modification. Reliable separation and quantification of these compounds is critical for quality control, process monitoring and regulatory compliance in chemical and industrial settings.

Objectives and study overview

This application note demonstrates the performance of a polar-deactivated capillary column for the simultaneous gas chromatographic analysis of n-alkyl N,N-dimethylamines, n-alkyl chlorides and n-alkyl alcohols ranging from C8 to C18. The study aims to achieve baseline resolution of 17 analytes with a simple temperature program and standard flame ionization detection.

Methodology

The separation was carried out by capillary gas chromatography with flame ionization detection. Sample injections were performed in split mode to prevent overload. A moderate temperature ramp provided efficient elution of early-eluting amines and later eluting alcohols and chlorides within a single run.

Used instrumentation

• Gas chromatograph fitted with flame ionization detector
• Column: SH-PolarWax, 30 m × 0.53 mm i.d., 0.25 µm film thickness (P/N 227-36254-01)
• Oven program: 100 °C initial, ramp at 8 °C/min to 250 °C, hold 5 min
• Injection: 0.5 µL, split ratio 1:40, injector temperature 250 °C
• Detector temperature: 250 °C
• Carrier gas: hydrogen at 40 cm/s (5.2 mL/min)
• Detector sensitivity: 128 × 10-11 AFS

Main results and discussion

The SH-PolarWax column provided sharp, symmetric peaks and baseline separation of all 17 components, demonstrating consistent retention time shifts with increasing alkyl chain length. Amines eluted earliest, followed by chlorides and alcohols, reflecting their polarity differences. The method showed excellent reproducibility (retention time RSD < 0.2 %) and linear calibration curves across a wide concentration range.

Benefits and practical applications

This one-column GC-FID approach simplifies workflows by allowing simultaneous analysis of structurally related classes without derivatization. It supports high-throughput quality control in manufacturing of surfactants, fine chemicals and polymers, and can be adopted in environmental monitoring of alkyl-based contaminants.

Future trends and possibilities

Integration of this polar column with mass spectrometric detection could enhance compound identification and trace-level quantification. Further development may include ultra-fast temperature programs for even shorter runtimes, use of green carrier gases or automated sample preparation to meet evolving demands in process analytics and environmental testing.

Conclusion

The SH-PolarWax column combined with GC-FID offers a robust, reproducible and straightforward method for the comprehensive analysis of long-chain amines, chlorides and alcohols. Its ease of use and broad applicability make it a valuable tool for laboratories requiring reliable separation of polar analytes.