Analysis of Polycyclic Aromatic Hydrocarbons in Soil with Agilent Bond Elut HPLC-FLD

Importance of the Topic

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants with known carcinogenic and mutagenic properties. Their strong affinity for organic matter in soil makes accurate trace-level analysis essential for environmental monitoring, risk assessment and regulatory compliance.

Goals and Overview of the Study

This work describes the development and validation of a rapid HPLC-fluorescence method for simultaneous determination of sixteen priority PAHs in soil. The method integrates a QuEChERS multiresidue extraction and cleanup procedure with a high-efficiency Agilent ZORBAX Eclipse PAH column and gradient elution to achieve sensitive, reproducible quantification at parts-per-billion levels.

Methodology and Instrumentation

• Sample collection and preparation: Soil samples were air-dried, sieved and homogenized.
• Extraction: QuEChERS AOAC buffered acetonitrile extraction with magnesium sulfate and sodium acetate to separate PAHs from the matrix.
• Cleanup: Dispersive SPE using primary secondary amine sorbent, C18 material and magnesium sulfate to remove acids, lipids and residual water.
• Chromatography: Agilent 1200 Series HPLC with ZORBAX Eclipse PAH column of 4.6 by 50 millimeter and 1.8 micrometer particle size.
• Detection: Fluorescence detection with three excitation/emission profiles to cover 15 PAHs; UV detection at 230 nanometers for acenaphthylene.
• Data processing: Agilent ChemStation software for peak integration and quantification.

Main Results and Discussion

• Separation: Baseline resolution of all sixteen PAHs achieved in under 14 minutes using a binary gradient of acetonitrile and water.
• Linearity: Calibration curves from 0 to 300 nanograms per gram with correlation coefficients above 0.999.
• Sensitivity: Limits of detection ranged from 0.005 to 0.78 nanograms per gram; limits of quantification from 0.02 to 1.6 nanograms per gram.
• Recovery and precision: Mean recoveries between 86.0 and 99.2 percent with relative standard deviations of 0.6 to 1.9 percent across three spiking levels.
• Matrix effects: QuEChERS cleanup effectively removed interferences, yielding clean baselines in blank soil extracts.

Benefits and Practical Applications

This approach offers a fast, cost-effective workflow suitable for routine environmental laboratories. Key advantages include minimal solvent evaporation, high throughput, reduced analyte loss of volatile PAHs, and compatibility with existing HPLC-FLD platforms. It supports regulatory monitoring of soil at trace levels and can be adapted to other complex matrices.

Future Trends and Opportunities

• Integration with high-resolution mass spectrometry to expand target analyte lists and improve confirmation of isomeric PAHs.
• Automation of QuEChERS protocols to further increase sample throughput and reduce manual handling.
• Adaptation of the method for field-deployable extraction devices enabling on-site screening.
• Combination with chemometric tools to predict contamination sources and fate in complex environmental scenarios.

Conclusion

The validated HPLC-FLD method coupled with QuEChERS extraction delivers rapid, reliable quantification of sixteen carcinogenic and non-carcinogenic PAHs in soil. Excellent recoveries, low detection limits and robust precision demonstrate its suitability for environmental monitoring and quality control applications.

Reference

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