DETERMINATION OF PAH In Particulate Matter PM10 with SPE/EVAporation

Significance of the Topic

Exposure to polycyclic aromatic hydrocarbons (PAH) bound to PM10 particles poses significant health risks due to their carcinogenic and mutagenic properties. Monitoring PM10-bound PAH levels is essential for evaluating ambient air quality, ensuring regulatory compliance, and informing pollution control strategies.

Objectives and Study Overview

The study aims to establish an automated workflow for the determination of six priority PAH (benzo(a)anthracene, chrysene, benzo(b,j,k)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, and dibenzo(a,h)anthracene) in PM10 samples, with a focus on precise quantification of benzo(a)pyrene.

Methodology

The analytical procedure comprises:

1. Microwave-assisted extraction of 1 cm x 1 cm PM10 filter segments using acetone/n-hexane with deuterated internal standards at 100°C for 20 minutes.
2. Automated solid-phase extraction (SPE) on a FREESTYLE system: conditioning of silica cartridges with dichloromethane and n-hexane, quantitative sample loading, rinsing with DCM/n-hexane (3:2), and nitrogen-assisted drying.
3. EVAporation concentration employing heat (40°C), vacuum (210 mbar), and shaking to reduce solvent volume to 3 mL, followed by nitrogen blow-down to dryness and backfill to 1 mL acetone.
4. Automatic transfer of final extracts to GC vials for analysis.

Used Instrumentation

• FREESTYLE system modules: BASIC, SPE, EVAporation, 6-solvent upgrade, and blow-down function.
• 6 mL silica SPE cartridges and specialized trays/racks for vials and cartridges.
• GC–MS: Agilent 6890N/5975B with DB-5 UI capillary column (30 m x 0.25 mm x 0.25 μm).
• Carrier gas: helium at 1.5 mL/min; injection volume: 1 μL in split/splitless mode; temperature program: 65°C (1 min) to 200°C at 16°C/min, then to 320°C at 8°C/min (hold 3 min).

Main Results and Discussion

The end-to-end process time per sample, including solvent exchange and vial transfer, is approximately 79 minutes. In a sevenfold determination of benzo(a)pyrene, the method achieved an average recovery of 100.3% (RSD 2.0%) at a spiked level of 30 ng, demonstrating high accuracy and precision.

Benefits and Practical Applications

Automation of SPE and concentration steps reduces hands-on time, enhances reproducibility, and minimizes solvent exposure. The robust workflow supports routine monitoring of ambient PM10 for PAH, aiding environmental agencies and laboratories in compliance with ISO and EU regulations.

Future Trends and Potential Applications

Advancements may include integration of multi-analyte capabilities for comprehensive air pollutant profiling, miniaturized extraction modules for on-site sampling, and coupling with high-resolution mass spectrometry for enhanced sensitivity and selectivity.

Conclusion

The presented SPE/EVAporation workflow on the FREESTYLE platform provides a rapid, precise, and reproducible method for quantifying priority PAH in PM10 samples. Its automation and high recovery rates make it suitable for routine air quality monitoring and regulatory compliance.

Reference

1. DIN EN ISO 15549:2008 – Air quality: Standard method for benzo(a)pyrene measurement in ambient air.
2. Commission Decision 2004/107/EC – Regulation of PAH and heavy metals in ambient air.
3. Official Journal of the Republic of Slovenia, 39/06 – National regulation on PAH in outdoor air.