ISCC: PAH Analysis: GC Column Selection and Best Practices for Success

Significance of PAH Analysis in Environmental and Food Safety

Incomplete combustion of coal, petroleum or wood generates polycyclic aromatic hydrocarbons (PAHs), many of which are carcinogenic. These contaminants can disperse via air particulates, soil and water, threatening ecosystems and the food chain. Regulatory bodies in the European Union and the US-EPA rely on accurate PAH quantification to enforce safety limits and protect public health.

Objectives and Study Overview

This study compares two capillary GC columns—the moderately polar Agilent J&W DB-EUPAH and the non-polar DB-5ms—for the separation of priority PAHs regulated by the EU 15+1 list and US-EPA methods. It discusses best practices to achieve rapid, high-resolution analysis of up to 24 PAH compounds, including challenging isomeric pairs such as benzofluoranthene isomers.

Methodology and Instrumentation

Key experimental parameters for both column approaches, performed on an Agilent 7890 GC coupled to a 5975C MS detector, include:

• Sample: 0.5 µL injection of 1–2 µg/mL mixed EU + EPA PAHs
• Carrier gas: He at 1.7–1.8 mL/min constant flow
• Columns:
  
  • DB-EUPAH, 20 m × 0.18 mm × 0.14 µm
  • DB-5ms, 20 m × 0.18 mm × 0.18 µm
• Oven programs tailored for each column to resolve low- and high‐boiling PAHs within 22–28 minutes
• Splitless inlet at 300 °C with timed purge flows and optional back-flush to minimize matrix effects and reduce cycle time
• MSD in SIM/Scan mode over 50–400 amu with source/transfer line at 340 °C

Main Results and Discussion

The DB-5ms column achieved baseline separation of 23 out of 24 EU + EPA PAHs in under 22 minutes, grouping benzo[b,j,k]fluoranthene isomers for quantitation when full resolution is not required. The DB-EUPAH column fully resolved all 24 target compounds, including benzofluoranthene isomers, in under 28 minutes. High-efficiency 0.18 mm ID columns and optimized temperature ramps improved peak shapes and reduced analysis time without sacrificing resolution.

Benefits and Practical Applications

This optimized methodology enables laboratories to:

• Comply with both EU and US-EPA PAH monitoring regulations using a single platform
• Achieve fast throughput with minimal sample carryover via post-run back-flush
• Adapt column choice to specific compound sets and analytical priorities

Future Trends and Opportunities

Advances in column technology point to even narrower bore diameters and novel stationary phases for enhanced sensitivity and faster separations. Integration of tool-free inlet modules, more robust back-flush systems and automated method optimization using AI-driven software will further streamline routine PAH analysis in environmental and food laboratories.

Conclusion

Selecting the appropriate GC column chemistry and optimizing operating conditions are critical to achieving rapid, high-resolution PAH separations. Both the DB-5ms and DB-EUPAH columns offer distinct advantages for US-EPA and EU analyses, respectively, while shared instrument methods facilitate flexible compliance strategies.

References

• Polycyclic Aromatic Hydrocarbon (PAH) Analysis Using an Agilent J&W DB-5ms Ultra Inert Capillary GC Column, Kenneth Lynam and Doris Smith, Agilent Publication 5989-9181EN
• GC/MS Analysis of European Union (EU) Priority Polycyclic Aromatic Hydrocarbons (PAHs) Using an Agilent J&W DB-EUPAH GC Column, Doris Smith and Ken Lynam, Agilent Publication 5990-4883EN
• PAH Analyses with High Efficiency GC Columns: Column Selection and Best Practices, Ken Lynam, Agilent Publication 5990-5872EN