Determination of polycyclic aromatic hydrocarbons in drinking water at ppt levels by Solid Phase Micro Extraction Arrow coupled with GC-MS

Significance of the topic

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants of global concern due to their ubiquity, toxicity and regulation in drinking water. They originate from incomplete combustion processes and industrial sources, and can leach into water distribution systems. Monitoring trace levels is critical for public safety and compliance with stringent regulatory limits.

Objectives and study overview

The study demonstrates a fully automated method for extraction and quantification of sixteen EPA priority PAHs in drinking water using Solid Phase Micro Extraction Arrow coupled with gas chromatography–mass spectrometry (GC-MS). The aim is to achieve ppt-level detection with improved sensitivity, reproducibility and ease of use.

Methodology and instrumentation

A 100 µm PDMS-coated SPME Arrow fiber was used for direct immersion extraction of 15 mL water spiked with deuterated internal standards. Samples were equilibrated and extracted at 35 °C under stirring, followed by thermal desorption into a Thermo Scientific TRACE 1310 GC with Instant Connect splitless injector and TG-5 SilMS column. Detection was performed on an ISQ single quadrupole MS in selected ion monitoring (SIM) mode. A TriPlus RSH autosampler enabled full automation of fiber conditioning, extraction and desorption steps.

Primary results and discussion

• Linearity over 1–500 ng/L with coefficients of determination ≥ 0.995
• Method detection limits of 0.5–3 ng/L, with 1 ng/L for benzo[a]pyrene
• Recoveries between 18 % and 96 % depending on compound polarity (log Kow)
• Up to fivefold increase in extraction response compared to classic 100 µm SPME fiber
• Precision with relative standard deviations < 13 %
• Low carry-over below 0.6 %
• Robust operation for over 150 injections without septum change

Benefits and practical applications

The solvent-free, automated workflow reduces sample preparation time, solvent use and contamination risk. The high sensitivity and precision meet regulatory requirements for drinking water analysis, making the method suitable for routine environmental and quality-control laboratories.

Future trends and opportunities

• Extension to broader classes of emerging contaminants
• Coupling with high-resolution mass spectrometry for enhanced selectivity
• Development of portable SPME Arrow devices for field monitoring
• Integration with headspace sampling for volatile pollutant analysis

Conclusion

This fully automated SPME Arrow GC-MS approach provides robust, sensitive and reproducible quantification of trace PAHs in drinking water. Its superior extraction efficiency and ease of use support compliance with stringent regulatory standards and facilitate routine monitoring.

Reference

1. US EPA Code of Federal Regulations Title 40 Subpart G 2002
2. Directive 2013/39/EU amending Directives 2000/60/EC and 2008/105/EC
3. Poerschmann J, Gorecki T, Kopinke FD Environ Sci Technol 2000 34 3824–3830
4. Baltussen E, David F, Sandra P, Jansen H-G, Cramer CA J Chromatogr A 1998 805 237–247
5. Kremser A, Jochmann MA, Schmidt TC Anal Bioanal Chem 2016 408 943–952
6. Cheng X, Forsythe J, Peterkin E Water Res 2013 47 2331–2340
7. Directive 2015/1787/EU on Quality of Water Intended for Human Consumption