Polycyclic aromatic hydrocarbons

Importance of the Topic

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants known for their toxic and carcinogenic properties. Accurate detection and quantification of PAHs are essential for regulatory compliance, human health risk assessment, and monitoring of soil and water quality.

Study Objectives and Overview

This application note describes a gas chromatography method based on EPA 8100 for the separation and analysis of 20 priority PAHs. Using an Agilent CP-Sil 8 CB capillary column, the method aims to achieve complete resolution of target compounds within 45 minutes, providing a reliable protocol for environmental laboratories.

Methodology and Instrumentation

• Technique: Capillary gas chromatography with flame ionization detection (GC-FID).
• Column: Agilent CP-Sil 8 CB, 0.32 mm × 25 m, 0.12 µm film thickness.
• Oven temperature program: 100 °C (2 min) ramped at 5 °C/min to 300 °C.
• Carrier gas: Hydrogen at 45 kPa.
• Injector: Split mode at 100 mL/min, 265 °C.
• Detector: FID at 325 °C.

Key Results and Discussion

The optimized method achieved baseline separation of all 20 EPA-listed PAHs, from naphthalene through high-molecular-weight dibenzopyrenes, in under 45 minutes. Chromatograms exhibited sharp, well-resolved peaks with consistent retention times, demonstrating the column's high efficiency and repeatability.

Benefits and Practical Applications

• High throughput: complete analysis in less than one hour.
• Regulatory compliance: meets EPA 8100 criteria for environmental monitoring.
• Robust performance: minimizes co-elution and enhances quantification accuracy.

Future Trends and Opportunities

Coupling GC with mass spectrometry (GC-MS) could lower detection limits and improve selectivity for trace PAH analysis. Development of novel stationary phases may further shorten run times and enhance resolution of structurally similar isomers.

Conclusion

The Agilent CP-Sil 8 CB column coupled with GC-FID provides a fast, reliable, and EPA-compliant method for comprehensive PAH analysis in environmental samples. This approach supports rigorous quality control and regulatory testing in modern analytical laboratories.

Instrumentation

• Gas chromatograph with flame ionization detector (FID).
• Agilent CP-Sil 8 CB capillary column (0.32 mm × 25 m, 0.12 µm).