Fast method to quantify PAHs in contaminated soils by direct thermodesorption using analytical pyrolysis.

Area of Science:

• Environmental Chemistry
• Analytical Chemistry

Background:

• Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants found in contaminated soils.
• Accurate quantification of PAHs is crucial for environmental risk assessment.

Purpose of the Study:

• To develop and validate a novel pyrolysis-based method for PAH quantification.
• To compare the performance of the new method against a conventional solvent extraction technique.

Main Methods:

• Development of a pyrolysis method at 450°C coupled with gas chromatography-mass spectrometry/flame ionization detection (Py-GC-MS/FID).
• Comparison with accelerated solvent extraction followed by GC-MS analyses.
• Analysis of various contaminated soil samples and a certified reference material (CRM).

Main Results:

• Good agreement between the pyrolysis method and the conventional method, particularly for the CRM.
• Reduced variability in soil sample analysis after particle size reduction (<100µm).
• Py-GC-MS/FID quantified higher levels of low molecular weight (LMW) PAHs.

Conclusions:

• The pyrolysis-based method is a faster, cost-effective, and environmentally friendly alternative for PAH quantification in soils.
• Limited sample preparation and absence of solvents contribute to the method's advantages.
• Potential for slight cracking or LMW PAH loss in conventional methods warrants consideration.