Select Polycyclic Aromatic Hydrocarbons (PAHs) on Rxi®-PAH

Significance of Analyzing PAHs

Polycyclic aromatic hydrocarbons (PAHs) pose significant health and environmental risks due to their carcinogenic and mutagenic properties. Accurate quantitation and separation of PAH mixtures are essential for environmental monitoring, regulatory compliance, and contamination assessment.

Study Objectives and Overview

This work aimed to establish a robust gas chromatography–mass spectrometry (GC–MS) protocol employing the Rxi®-PAH column to resolve a comprehensive panel of 48 PAHs, including critical isobaric pairs, and to demonstrate method sensitivity and reproducibility.

Methodology

Sample preparation consisted of dissolving a PAH standard mixture containing native and deuterated internal standards in dichloromethane. A 1 µL aliquot was injected in split mode (10:1) onto the Rxi®-PAH capillary column (60 m × 0.25 mm ID, 0.10 µm film). The oven temperature program initiated at 110 °C, ramped to 210 °C and 295 °C at controlled rates, with a final hold at 350 °C. Helium served as the carrier gas at a constant flow of 1.95 mL/min.

Instrumentation

• GC: Agilent 7890B equipped with Rxi®-PAH column (cat. 49317)
• MS: Agilent 5977A in SIM mode, EI ionization
• Transfer line: 330 °C; Source temp: 350 °C; Quad temp: 200 °C
• Injector: Premium 4 mm wool liner at 275 °C

Main Results and Discussion

The method achieved baseline separation of all 48 target PAHs, including challenging isobars such as cyclopenta[cd]pyrene/triphenylene/chrysene and benzo[b,k,j]fluoranthenes. Quantitation limits ranged from 0.07 to 0.63 µg/mL for native compounds and 2.0 µg/mL for labeled standards. Scan groups in SIM mode improved selectivity and sensitivity.

Practical Benefits and Applications

• Environmental monitoring of air, water, and soil matrices
• Quality control in petrochemical and food industries
• Regulatory compliance with EPA and EU guidelines

Future Trends and Opportunities

Advances may include faster temperature programming, ultra-high-resolution MS for non-target screening, micro-GC modules for field deployment, and integrated data analytics for automated reporting.

Conclusion

The developed GC–MS method on an Rxi®-PAH column provides a reliable, sensitive, and reproducible platform for comprehensive PAH analysis. Its ability to separate structurally similar compounds enhances confidence in environmental and industrial monitoring.

References

Restek Corporation. Application Note: Select Polycyclic Aromatic Hydrocarbons on Rxi®-PAH.