Analysis of polynuclear aromatic hydrocarbons (PAH)

Importance of the topic

Polynuclear aromatic hydrocarbons (PAHs) represent a class of persistent organic pollutants with known carcinogenic and mutagenic properties. Accurate analysis of PAHs is critical for environmental monitoring, food safety testing and regulatory compliance in various industrial and research settings.

Goals and overview of the study

This application note presents a gas chromatographic method using a BPX5 column for the simultaneous separation and detection of 16 priority PAHs. The protocol aims to deliver baseline resolution within a single run, ensuring reliable identification and quantification for routine laboratory workflows.

Used Instrumentation

• Gas chromatograph equipped with flame ionization detector (FID)
• BPX5 column (30 m × 0.22 mm ID × 0.25 μm film thickness, part no. 054142)
• Carrier gas: Helium at 20 psi
• Temperature program: 100 °C (1 min hold) to 380 °C (20 min hold) at 5 °C/min
• FID operating temperature: 370 °C

Methodology

Samples containing PAH mixtures are introduced via split/splitless injection (conditions adjusted per laboratory requirements). The column oven ramps from 100 °C to 380 °C at 5 °C/min, providing efficient separation across two- to six-ring PAHs. Detector response is recorded under constant flow, yielding reproducible retention times and peak shapes for quantitative analysis.

Main results and discussion

The developed method achieves baseline separation of 16 PAHs, from naphthalene through benzo(g,h,i)perylene, within an approximate 50-minute run time. Key observations include sharp peak profiles and consistent retention ordering, supporting reliable compound identification. The broad temperature range ensures elution of both low- and high-molecular-weight PAHs without peak co-elution or thermal degradation.

Benefits and practical use of the method

• Robust separation of a comprehensive PAH panel in a single analysis
• Flame ionization detection offers broad linear response and ease of maintenance
• Sufficient thermal stability for high-boiling PAHs
• Applicable to environmental, food safety and industrial quality-control laboratories

Future trends and opportunities

Emerging developments may include coupling to mass spectrometric detectors for enhanced selectivity, faster temperature programming for reduced analysis time, and the adoption of micro- and capillary GC technologies for field-deployable applications. Two-dimensional GC (GC×GC) also holds potential for further resolution of complex PAH mixtures.

Conclusion

The BPX5-based GC-FID method outlined here provides a straightforward and reliable protocol for the analysis of 16 priority PAHs. Its balance of resolution, run time and operational simplicity makes it well-suited for routine monitoring and regulatory compliance.

References

Trajan Scientific Australia Pty Ltd. Application Note AN-0081-G, December 2016