Analysis of Volatile PFAS in Water Using Head-Space Solid Phase Microextraction- Gas Chromatography/Mass Spectrometry (HS-SPME GC/MS)

Importance of the Topic

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants with known health risks. Their widespread use and stability in water necessitate robust analytical methods to monitor volatile PFAS species that are not readily covered by standard LC/MS protocols. Head-space solid phase microextraction (HS-SPME) coupled with gas chromatography–mass spectrometry (GC/MS) offers a complementary approach, enabling trace-level detection with minimal sample preparation and reduced contamination risk.

Objectives and Study Overview

This study presents the development and validation of an HS-SPME GC/MS method for the analysis of volatile PFAS in water. Target analytes include perfluoroalkyl iodides, fluorotelomer iodides, acrylates, methacrylates, alcohols, and sulfonamides. A Shimadzu GCMS-QP2020 NX paired with an AOC-6000 Plus autosampler was employed to achieve automated, high-throughput analysis.

Methodology and Instrumentation

• Sample Preparation: 10 mL water samples spiked with mass-labelled internal standards, salted with 2% NaCl to enhance head-space partitioning.
• HS-SPME Extraction: 50/30 μm DVB/CAR/PDMS fiber, 5 min incubation at 50 °C, 30 min extraction, 7 min desorption at 240 °C.
• GC/MS Conditions: Splitless injection, SH-I-624Sil MS capillary column (30 m×0.25 mm, 1.40 μm); oven ramp from 40 °C to 300 °C; helium carrier gas; QP2020 NX in SIM mode for targeted quantitation.

Key Results and Discussion

• Chromatographic Separation: All 13 target PFAS resolved in total ion chromatography, with co-eluting pairs distinguished by unique SIM ions.
• Linearity: Calibration ranges from 2.5 to 2000 ng/L across compounds; correlation coefficients (R²) ≥ 0.993; response factor RSDs < 20%.
• Sensitivity and Carryover: Detection limits at low ng/L; laboratory blanks showed no PFAS contamination; carryover below 0.2% after high-level standards.

Benefits and Practical Applications

This HS-SPME GC/MS workflow minimizes solvent use and manual steps, reducing sources of contamination and operator error. The fully automated AOC-6000 Plus sampler enhances throughput and reproducibility. The single quadrupole GC/MS platform provides a cost-effective alternative to high-resolution or triple quadrupole systems for routine monitoring of volatile PFAS in environmental and industrial waters.

Future Trends and Potential Applications

• Method extension to complex matrices such as wastewater, soils, and biota.
• Integration with online monitoring systems for real-time PFAS surveillance.
• Coupling with high-resolution MS to expand target lists and improve structural elucidation.
• Development of novel SPME coatings for broader PFAS coverage and enhanced sensitivity.

Conclusion

The validated HS-SPME GC/MS method on the Shimadzu GCMS-QP2020 NX and AOC-6000 Plus demonstrates robust, sensitive, and reproducible analysis of volatile PFAS in water. Its streamlined sample preparation and automation capabilities make it well suited for routine environmental monitoring and regulatory compliance.

References

1. Bach C et al. Simultaneous determination of perfluoroalkyl iodides, sulfonamides and fluorotelomer species in water and sediments using solid-phase microextraction-GC/MS. J Chromatogr A 1448:98–106 (2016).
2. Shimadzu Smart SPME Fibers and Arrow Selection Guide C146-E424A.