Determination of Polycyclic aromatic hydrocarbons in soils using the EXTREVA ASE Accelerated Solvent Extractor and GC-MS

Significance of the Topic

Polycyclic aromatic hydrocarbons are widespread environmental pollutants known for their toxicity, carcinogenicity and persistence in soil. Reliable analysis of PAHs at trace levels is essential for regulatory compliance, risk assessment and remediation studies.

Objectives and Study Overview

This study presents a fully automated workflow for extracting and quantifying 16 priority PAHs in soil using an accelerated solvent extraction and evaporation platform paired with gas chromatography mass spectrometry. The method follows US EPA guidelines to achieve high throughput and minimal solvent consumption.

Methodology and Instrumentation

Soil samples were spiked with PAH standards and mixed with a dispersant to ensure uniform extraction. Accelerated solvent extraction was performed under elevated temperature and pressure with a gas assist to enhance recovery. Extracts were automatically evaporated to a fixed volume and spiked with internal standards prior to GC MS analysis. Calibration was conducted over six concentration levels, yielding linear or quadratic response with errors under 10 percent.

Used Instrumentation

• EXTREVA ASE Accelerated Solvent Extractor and Evaporator System
• TRACE 1310 Gas Chromatograph
• ISQ 7000 Single Quadrupole Mass Spectrometer
• Rocket Synergy 2 Evaporator System
• Dionex ASE Collection Vials and Dispersants

Main Results and Discussion

The method delivered recoveries between 77 and 113 percent for all PAHs with relative standard deviations below 20 percent for both 10 and 100 mL cell sizes. Concentration experiments demonstrated minimal analyte loss, with recoveries from 77 to 105 percent and RSDs under 15 percent. Carryover tests showed less than 0.5 percent cross contamination. Certified reference material analysis matched the certified ranges, confirming accuracy and reproducibility.

Benefits and Practical Applications

• Fully automated extraction and evaporation reduces manual steps and errors
• Significant reduction in solvent usage compared to Soxhlet or sonication
• High throughput with unattended operation of up to 16 samples in parallel
• Compliance with US EPA methods for PAH determination in soil
• Robust performance for routine environmental monitoring and quality control

Future Trends and Applications

Advances in solvent exchange and sample handling automation may further improve selectivity and recovery for diverse matrices. Integration with laboratory information management systems and artificial intelligence for method optimization will enable adaptive workflows. The approach can extend to other semi volatile organic pollutants, supporting broader environmental and food safety applications.

Conclusion

The combination of accelerated solvent extraction and automated evaporation in a single platform provides an efficient, reliable and high throughput solution for PAH analysis in soils. This integrated method meets stringent regulatory criteria, reduces solvent consumption and streamlines laboratory workflows.

References

1. Patel AB and colleagues, Polycyclic Aromatic Hydrocarbons Sources, Toxicity, and Remediation, Frontiers in Microbiology, 2020
2. US EPA Method 3500 for sample extraction guidance
3. US EPA Method 8100 for chromatographic analysis
4. US EPA Method 8270 for semivolatile organic compounds by GC MS
5. US EPA Method 3545A for pressurized fluid extraction
6. Srinivasan K and Ullah R, US Patent 9,440,166, Gas Assisted Extraction, 2016
7. Srinivasan K and Ullah R, US Patent 11,123,655, Parallel Accelerated Solvent Extraction, 2021
8. US EPA Test Method 8000D for chromatographic separations