Analysis of Low-Level PAHs in Drinking Water with an Agilent PAL3 equipped with SPME ARROW

Significance of the Topic

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants formed during incomplete combustion of organic matter. Due to their potential carcinogenicity and persistence, regulatory bodies enforce strict limits for PAH concentrations in drinking water. Rapid, sensitive, and reliable monitoring methods are essential to ensure compliance and protect public health.

Objectives and Study Overview

This study presents an automated, low-level PAH analysis workflow based on solid-phase microextraction (SPME) Arrow technology coupled to GC–MS. The goals were to demonstrate:

• Efficient extraction of 16 priority PAHs from drinking water.
• Sufficient sensitivity to quantify analytes at sub-ng/L levels.
• High reproducibility over extended sample batches.

Instrumentation Used

• Agilent 7890B gas chromatograph with split/splitless inlet.
• Agilent 5977B GC/MSD with extractor source.
• Agilent PAL3 RSI 120 autosampler equipped with SPME Arrow (100 µm PDMS, 3.8 µL phase volume).
• Agilent J&W DB-EUPAH GC column (30 m × 0.25 mm × 0.25 µm).

Methodology and Procedure

Sample preparation and analysis were fully automated on the PAL3. Drinking water samples (15 mL) spiked with calibration or internal standards underwent:

• Preconditioning of fiber at 280 °C for 15 min.
• Extraction at 40 °C under stirring (500 rpm) for 30 min after 5 min incubation.
• Thermal desorption in the GC inlet at 280 °C for 5 min.
• Postdesorption fiber conditioning for 15 min.

Chromatographic conditions: inlet liner optimized for SPME Arrow, oven program from 40 °C (2 min) to 260 °C at 20 °C/min, then to 335 °C at 6 °C/min. Transfer line at 320 °C. MS operated in SIM mode (source 320 °C, quadrupole 150 °C). Calibration standards ranged from 1 to 200 ng/L, using deuterated internal standards at 50 µg/mL.

Main Results and Discussion

The method achieved excellent linearity for all 16 PAHs, with correlation coefficients (R²) ≥ 0.999 (dibenz[a,h]anthracene R² = 0.9989) across 1–200 ng/L. Reproducibility testing (11 injections of 10 ng/L) yielded relative standard deviations below 8% for all analytes. The SPME Arrow fiber demonstrated high mechanical stability, retaining performance through over 200 sample runs. Limits of detection were below 1 ng/L, meeting regulatory requirements.

Benefits and Practical Applications

This approach combines sample preparation and analysis into a single automated workflow, reducing solvent use and hands-on time. The enhanced phase volume of the SPME Arrow improves sensitivity for trace-level PAH quantification in matrices such as drinking water. Laboratories tasked with routine environmental monitoring can adopt this method to increase throughput and reliability.

Future Trends and Applications

Advances in microextraction materials will further drive detection limits lower while maintaining robustness. Integration with high-resolution MS and miniaturized GC platforms may enable on-site or real-time PAH screening. Expanded applications could include monitoring of PAHs in complex matrices such as wastewater, biota, and soil pore water.

Conclusion

An Agilent PAL3 SPME Arrow workflow coupled to GC–MS provides an efficient, sensitive, and reproducible method for low-level PAH analysis in drinking water. The method meets stringent detection requirements and supports high-throughput environmental monitoring.

References

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3. European Commission. GC/MS Analysis of EU Priority Polycyclic Aromatic Hydrocarbons (PAHs) Using an Agilent J&W DB-EUPAH GC Column: Column Performance Comparison. Agilent Technologies Application Note 5990-4883EN.
4. Agilent Technologies. Analysis of Low-Level Polycyclic Aromatic Hydrocarbons (PAHs) in Rubber and Plastic Articles Using Agilent J&W DB-EUPAH GC Column. Application Note 5990-6155EN.
5. Agilent Technologies. PAH Analyses with High Efficiency GC Columns: Column Selection and Best Practices. Application Note 5990-5872EN.
6. Gardner MJ, Wilson AL, Cheesman RJ. A Manual on Analytical Quality Control for the Water Industry NS30. WRc Medmenham; 1989.