Aromatics - Fast analysis of BTX

Significance of Rapid BTX Monitoring

In environmental monitoring, timely detection of benzene, toluene, ethylbenzene and xylenes (BTX) is critical for assessing air quality and ensuring compliance with regulatory standards. A fast, sensitive analytical method enables on-site decision making and reduces exposure risks to harmful volatile organic compounds.

Study Objectives and Overview

This application note demonstrates a fast, field-deployable approach for analyzing BTX in ambient air using the Agilent 490 Micro GC equipped with a CP-Sil 8 CB column. The goal is to achieve complete separation and quantification of target aromatics within 150 seconds at concentration levels down to parts per million.

Methodology

The analytical procedure was optimized for rapid temperature-isothermal operation and minimal sample volume. Key operating parameters include:

• Column temperature: 60 °C
• Carrier gas: Helium at 150 kPa (1.5 bar)
• Injection time: 100 ms without heated inlet
• Sample matrix: Ambient air
• Concentration range: Approximately 100 ppm for each component

Instrumentation Used

• Agilent 490 Micro Gas Chromatograph
• Agilent CP-Sil 8 CB fused-silica WCOT column (0.1 mm × 4 m, part CP737053)

Main Results and Discussion

The system achieved baseline resolution of six peaks within a 150 second analysis time. Peak identification order was:

1. Air and residual moisture
2. Benzene
3. Toluene
4. Ethylbenzene
5. m- and p-Xylenes
6. o-Xylene

Detection at ppm levels was demonstrated with sharp, reproducible peaks and stable baselines. The isothermal method simplifies hardware requirements and reduces cycle time compared to conventional GC.

Benefits and Practical Applications

• On-site air quality assessment for environmental agencies and industrial facilities
• Rapid feedback for process control in petrochemical and manufacturing plants
• Portable, low-power operation suitable for remote monitoring
• Minimal carrier gas and sample consumption

Future Trends and Potential Applications

• Extension to additional volatile organic compounds and odorants
• Integration with wireless networks for real-time data reporting
• Further miniaturization of GC modules for handheld devices
• Coupling with advanced detectors (e.g., mass spectrometry, IMS) for enhanced specificity

Conclusion

The Agilent 490 Micro GC with a CP-Sil 8 CB column provides a robust, rapid solution for BTX monitoring in air. Its fast analysis time, low detection limits and portability make it a valuable tool for environmental monitoring and industrial process control.