A rapid, sensitive, and consolidated method for PCBs and PAHs using GC-MS/MS

Importance of Topic

Persistent organic pollutants such as polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) are major environmental hazards. Their resistance to degradation and ability to bioaccumulate in food chains demand sensitive, reliable analytical methods. A consolidated approach that quantifies both classes of compounds in a single rapid run enhances laboratory productivity, ensures regulatory compliance, and reduces sample volume and preparation time.

Objectives and Study Overview

The study aimed to demonstrate the quantitative performance of the Thermo Scientific TSQ 9610 triple quadrupole GC-MS/MS system with the Advanced Electron Ionization source. Key goals included:

• Developing a single-run method for PAHs and PCBs in water.
• Achieving regulatory limits with reduced analysis time.
• Evaluating linearity, limits of quantitation, and robustness across a broad concentration range.

Methodology and Instrumentation

Sample Preparation

• Liquid–liquid extraction: 250 mL water sample with 5 mL hexane/heptane/cyclohexane.
• Concentration: Evaporation to 500 µL, reconstitution with 500 µL acetonitrile.
• Injection of the lower acetonitrile phase.

Instrumentation

• GC: Thermo Scientific TRACE 1610 with programmable temperature vaporizing inlet.
• Column: TraceGOLD TG-17SilMS (30 m × 0.25 mm × 0.25 µm).
• MS/MS: Thermo Scientific TSQ 9610 triple quadrupole with NeverVent Advanced Electron Ionization source and XLXR detector.
• Autosampler/Data System: AS 1310 autosampler, iConnect-PTV, Chromeleon CDS software.

Chromatography

• Total run time: 24 minutes.
• Carrier gas: Helium at 1.5 mL/min.
• Temperature program optimized to separate critical isobaric pairs.

Main Results and Discussion

The method successfully separated all critical isobaric pairs (e.g., PCB 28/PCB 31, anthracene/phenanthrene) with chromatographic resolution ≥0.7. Linearity was demonstrated over 0.4–300 µg/L with R² >0.99. Limits of quantitation for all analytes were ≤0.4 µg/L, with signal-to-noise ratios >10 at the LOQ. Reproducibility tests (10 injections at 0.4 µg/L) yielded relative standard deviations below 25%. Robustness over 80 sequential injections showed consistent calculated concentrations and stable resolution for key compounds.

Benefits and Practical Applications

The consolidated GC-MS/MS method:

• Reduces analysis time by combining PAH and PCB assays into one run.
• Lowers solvent and sample volume requirements.
• Improves selectivity and confidence in complex matrices by reducing interferences.
• Supports high throughput with minimal downtime via NeverVent technology.

Future Trends and Potential Applications

Advances may include coupling this platform with automated sample preparation, expanding the compound scope to emerging contaminants, implementing real-time data processing with AI-driven algorithms, and integrating with field-deployable GC-MS solutions for on-site monitoring.

Conclusion

The Thermo Scientific TSQ 9610 GC-MS/MS system with Advanced Electron Ionization delivers a robust, sensitive, and rapid method for simultaneous PAH and PCB analysis in water. With excellent linearity, low quantitation limits, reliable reproducibility, and streamlined workflow, it meets stringent regulatory demands and supports high laboratory throughput.

Reference

Guidance on information requirements and chemical safety assessment, Part C: PBT/vPvB, ECHA, May 2018.