Halogenated hydrocarbons in water - Separation of volatile halogenated hydrocarbons in water on a wide-bore fused silica capillary column

Significance of the Topic

Volatile halogenated hydrocarbons are widely used in industrial processes and can contaminate water supplies. These compounds are often toxic and persistent in the environment. Reliable analysis supports environmental monitoring and regulatory compliance.

Study Objectives and Overview

The objective was to demonstrate fast and efficient separation of 14 halogenated hydrocarbons in water using a wide-bore fused silica capillary column. The method achieves complete resolution within 15 minutes, making it suitable for routine environmental analysis.

Methodology and Instrumentation

Headspace sampling of water was coupled to gas chromatography with flame ionization detection. Key steps include:

• Injection of 5 μL headspace sample
• Temperature program from 50 °C (1 min) to 250 °C at 10 °C/min
• Hydrogen carrier gas at 65 kPa providing an optimal linear velocity

Main Results and Discussion

All 14 target compounds were baseline separated in under 15 minutes. The compounds spanned from dichloromethane to 1,2,4-trichlorobenzene. Peak shapes were sharp and symmetric, indicating efficient mass transfer. The method delivered consistent retention times with high reproducibility.

Benefits and Practical Applications

• Rapid analysis reduces sample turnaround time
• Simplified headspace sampling minimizes solvent use
• Wide-bore column ensures robust performance with minimal maintenance
• Applicable for environmental monitoring and quality control

Future Trends and Opportunities

Advances may include coupling headspace GC to mass spectrometry for enhanced specificity and lower detection limits. Portable GC systems offer on-site monitoring potential. Automation of sample preparation can further improve throughput.

Conclusion

The demonstrated method provides a reliable, fast, and reproducible approach for analyzing a broad range of halogenated hydrocarbons in water, supporting environmental safety and regulatory demands.

Used Instrumentation

• GC-capillary system with CP-Sil 5 CB, 0.53 mm × 50 m fused silica column, film thickness 5 μm
• Flame ionization detector at 300 °C
• Hydrogen carrier gas at 65 kPa
• Direct injection at 225 °C