PAHs - Analysis of EPA 610 polyaromatic hydrocarbons

Importance of the Topic

Polyaromatic hydrocarbons (PAHs) are persistent organic pollutants with mutagenic and carcinogenic properties. Their trace-level determination in environmental matrices is essential for regulatory compliance and public health risk assessment. High sensitivity and accuracy are required to detect PAH concentrations at parts-per-trillion levels, driving continuous refinement of analytical methods.

Objectives and Overview

This study outlines a gas chromatography with flame ionization detection (GC-FID) approach for the quantitative analysis of the 16 EPA 610 priority PAHs. It compares direct on-column injection for environmental samples with split injection for standard mixtures, demonstrating method performance in terms of sensitivity, resolution, and reproducibility.

Methodology and Instrumentation

The method employs a 0.53 mm i.d. × 30 m Agilent VF-5ms capillary column with a 0.5 µm film thickness. Two injection protocols are described:

• Environmental samples: direct on-column injection of 2 µL sample (≈10 pg/µL), temperature program 50 °C (6 min) to 300 °C at 10 °C/min, helium carrier gas at 50 cm/s, FID at 300 °C.
• Standard mixtures: split injection delivering ~10 ng of each PAH, temperature program 40 °C (4 min) to 270 °C at 10 °C/min, hydrogen carrier gas at 50 kPa, FID at 300 °C.

Main Results and Discussion

The optimized conditions provided baseline separation of all 16 priority PAHs, including low-volatility heavy congeners such as benzo(g,h,i)perylene. The on-column approach minimized discrimination and thermal degradation for volatile PAHs, achieving detection limits near 10 pg. Reproducibility studies showed retention time RSDs below 1% and peak area RSDs below 5%.

Benefits and Practical Applications

The combination of on-column injection and nonpolar stationary phase yields robust, high-sensitivity measurements suitable for environmental monitoring, food safety testing, and quality control in industrial processes. The method’s adaptability to both helium and hydrogen carrier gases allows flexible laboratory integration.

Future Trends and Potential Applications

Advancements may include coupling with mass spectrometric detection for enhanced selectivity, rapid temperature programming for shorter analysis times, and microfabricated columns for field-deployable PAH monitoring. Automation and data-processing improvements will further support large-scale environmental surveys.

Conclusion

The described GC-FID method delivers reliable trace-level determination of EPA 610 PAHs with excellent resolution and repeatability. Its straightforward implementation and compatibility with routine environmental laboratory infrastructure make it a valuable tool for regulatory and research applications.

Instrumentation Used

• Agilent 7890A GC system with 0.53 mm × 30 m VF-5ms column (0.5 µm film)
• On-column injector and split injection port
• Flame ionization detector (FID) at 300 °C
• Carrier gases: helium (50 cm/s) and hydrogen (50 kPa)