PAHs

Importance of the Topic

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants with recognized carcinogenic and mutagenic properties. Monitoring PAH levels in air, water, soil, and process streams is essential for regulatory compliance and risk assessment. Rapid, reliable analytical methods help laboratories meet strict quality requirements and support environmental protection efforts.

Objectives and Study Overview

This application note describes a fast gas chromatographic method for the simultaneous quantitation of 16 priority PAHs according to EPA Method 610. The primary aim is to achieve complete separation and accurate detection in under 23 minutes, enabling high sample throughput for routine environmental analysis.

Methodology and Instrumentation

Analytical conditions were optimized to maximize resolution and speed:

• Technique: Gas chromatography with flame ionization detection (GC-FID)
• Column: Agilent FactorFour EZ-Guard VF-5ms, 0.25 mm × 30 m, 0.25 μm film plus 10 m guard
• Temperature program: 50 °C initial hold 0.8 min, ramp 20 °C/min to 320 °C
• Carrier gas: Hydrogen at constant pressure (60 kPa)
• Injector: Splitless mode, 1 μL sample injection
• Detector: FID at 300 °C
• Sample solvent: Methanol containing approximately 1 ng/μL of each PAH

Instrumentation Used

The method was carried out on an Agilent GC system equipped with VF-5ms EZ-Guard columns and an FID module. Hydrogen was used for rapid elution and optimal peak shape.

Main Results and Discussion

All 16 target PAHs, including naphthalene, phenanthrene, benzo(a)pyrene, and benzo(g,h,i)perylene, were baseline separated within a total run time of less than 23 minutes. Retention time reproducibility and peak resolution met or exceeded EPA criteria. The method provided clear identification of early-eluting low molecular weight PAHs and late-eluting high molecular weight species.

Benefits and Practical Applications

This rapid GC-FID procedure offers several advantages:

• High throughput allowing large sample batches per day
• Cost effectiveness by using FID rather than mass spectrometry for routine screening
• Robust performance for environmental monitoring, industrial QC, and remediation studies

Future Trends and Potential Applications

Opportunities for further enhancement include coupling to mass spectrometry for increased selectivity, miniaturized columns for even faster analysis, automated sample preparation to reduce manual handling, and greener carrier gases or solvent alternatives to minimize environmental impact.

Conclusion

The described GC-FID method using Agilent VF-5ms EZ-Guard columns delivers fast, reproducible separation of 16 priority PAHs in under 23 minutes. It meets regulatory requirements while supporting high-throughput environmental and industrial analyses.

References

• Agilent Technologies Inc Application Note A02209, October 2011