Consolidated GC-MS/MS Analysis of OCPs, PAHs, and PCBs in Environmental Samples

Significance of Topic

Environmental monitoring of persistent semivolatile pollutants such as organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) is critical to assess human exposure and ecosystem health. These analytes are regulated worldwide due to their toxicity, persistence and bioaccumulation potential. Consolidating multiple target classes into a single streamlined GC-MS/MS method enhances laboratory throughput, reduces sample handling and cuts operational costs while maintaining rigorous performance and compliance with regulatory standards.

Objectives and Study Overview

The study aimed to develop and validate a single gas chromatography–tandem mass spectrometry (GC-MS/MS) method for simultaneous analysis of OCPs, PAHs and PCBs in diverse environmental matrices (water, soil, building materials). Key goals included optimizing chromatographic separation of critical isomers, demonstrating high repeatability and linearity, and integrating automated software tools to accelerate method development and routine implementation.

Methodology and Used Instrumentation

Sample Preparation

• Water: Liquid–liquid extraction with n-hexane, phase separation, drying over Na2SO4, concentration to final extract volume under nitrogen.
• Solid matrices: Sonication of 10 g sample with hexane/acetone and Na2SO4, dual extraction, Kuderna-Danish concentration to final volume.

GC-MS/MS Conditions

• Gas chromatograph: Thermo Scientific TRACE 1310 with TG-XLBMS column (20 m × 0.18 mm, 0.18 µm).
• Injection: 1 µL, splitless on Siltec baffled liner, PTV program for transfer and clean steps.
• Oven program: 60 °C hold, ramp 30 °C/min to 200 °C, then 10 °C/min to 320 °C.
• Mass spectrometer: Thermo Scientific TSQ 8000, EI at 70 eV, Q1 normal resolution, argon collision gas.
• Acquisition: Automated AutoSRM workflow from full-scan to optimized SRM transitions; timed-SRM windows for each analyte.

Main Results and Discussion

Chromatography and Robustness

• All target compounds eluted within 17 min with baseline resolution of critical isomer pairs (e.g., phenanthrene/anthracene, benzo[b]/benzo[k]fluoranthene).
• Retention times and peak shapes remained stable after over 100 injections of mixed environmental extracts.

Calibration and Linearity

• PAHs: 2–2500 µg/L; OCPs and PCBs: 2–700 µg/L.
• Correlation coefficients (R²) > 0.995 for all compounds; representative R² values ranged from 0.9985 to 0.9999.

Sensitivity and Precision

• Limits of quantitation at 2 µg/L (2 pg on column) produced signal-to-noise ratios > 10 for all analytes.
• Repeatability in matrix-spiked samples (water, soil, building material) yielded RSDs < 10% for all compounds.
• Ion ratio stability met EU performance criteria, with RSDs below 6% for monitored transitions.

Benefits and Practical Applications

• Consolidation of three traditional methods into one reduces instrument time and consumables.
• Automated software tools (AutoSRM, TraceFinder) minimize manual method setup and ensure reproducible performance across users.
• High selectivity and sensitivity of triple quadrupole MS/MS improves confidence in trace-level detection within complex matrices.
• Suitable for routine compliance testing, contract laboratories and large-scale environmental surveys.

Future Trends and Opportunities

• Expansion of GC-MS/MS panels to include emerging organic pollutants such as transformation products and novel flame retardants.
• Integration of high-throughput robotics for sample preparation and direct instrument control.
• Implementation of real-time data analytics and cloud-based compound libraries to accelerate method adaptation.
• Development of miniaturized GC-MS/MS platforms for on-site environmental screening.

Conclusion

The consolidated GC-MS/MS method using the TRACE 1310 and TSQ 8000 platforms delivers rapid, high-performance analysis of OCPs, PAHs and PCBs across varied environmental matrices. Automated method development and robust performance metrics ensure laboratories can achieve regulatory compliance with streamlined workflows and enhanced productivity.

References

1. Kalachova, T. et al. Analysis of emerging persistent organic pollutants using GC-MS/MS. SETAC, Berlin 2012.
2. Ziegenhals, K.; Hübschmann, H.J. Fast-GC/HRMS to quantify EU priority PAHs. J. Sep. Sci. 2008, 31, 1779–1786.
3. Cole, J. Introducing AutoSRM: MRM Simplicity for High Performance Results. Thermo Scientific Application Brief AB52998.
4. European Commission Regulation (EC) No. 2002/657 on analytical performance criteria.