Analyzing Wastewater Effluents for PAH’s and PBDE’s Using the Agilent 7000 Triple Quadrupole GC/MS

Importance of the Topic

Polyaromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs) are persistent organic contaminants that pose significant risks to aquatic ecosystems and human health. Monitoring their occurrence in wastewater effluents is critical to meet regulatory standards under the European Union Water Framework Directive and the UK Chemical Investigations Programme (CIP).

Objectives and Study Overview

The primary goal of this study was to develop a streamlined analytical workflow on the Agilent 7000 Triple Quadrupole GC/MS system for simultaneous quantification of eight PAHs and six PBDEs in wastewater. The method aimed to satisfy the stringent detection and reporting limits defined by the CIP without requiring extensive sample cleanup or solvent exchanges.

Methodology

• Sample preparation involved addition of aqueous ammonia to a 100 mL wastewater aliquot, followed by liquid–liquid extraction with hexane over 12 hours.
• A 5 mL portion of the organic phase was concentrated under nitrogen to 250 µL for direct GC/MS/MS analysis.
• Calibration standards were prepared in hexane containing deuterated and 13C-labeled internal standards to ensure accurate quantitation.

Instrumentation Used

• GC: Agilent 7890A equipped with a multimode inlet in solvent vent mode and an HP-5 column (30 m×0.25 mm, 0.25 µm).
• MS: Agilent 7000B Triple Quadrupole operated in electron ionization mode with multiple reaction monitoring, using helium as carrier and quench gas and nitrogen as collision gas.
• Total chromatographic run time was 20 minutes, achieving baseline separation for most analytes.

Main Results and Discussion

Chromatographic separation resolved 14 target compounds within 20 minutes, with only partial overlap of benzo(b)fluoranthene and benzo(k)fluoranthene. Calibration curves exhibited correlation coefficients above 0.999 for all analytes. Limits of detection ranged from 0.06 ng/L (PBDE 28) to 3.0 ng/L (benzo(b)fluoranthene), all below CIP analytical quality control thresholds.

Benefits and Practical Applications

• Single-step extraction with no further cleanup simplifies laboratory workflow and reduces solvent usage.
• High sensitivity and reproducibility support routine compliance monitoring and risk assessment.
• The method can be adapted for process streams, final effluents, and sludge across municipal and industrial wastewater treatment applications.

Future Trends and Opportunities

• Integration of automated solid-phase microextraction or on-line sample preparation to further increase throughput.
• Adoption of high-resolution mass spectrometry and data-driven analytics for screening of additional emerging pollutants.
• Development of portable GC/MS platforms for in-field monitoring and rapid decision making.

Conclusion

This validated GC/MS/MS approach delivers rapid, sensitive, and robust quantitation of PAHs and PBDEs in wastewater, exceeding UK CIP reporting requirements. Its minimal sample preparation and high analytical performance make it a valuable tool for environmental laboratories tasked with regulatory compliance and water quality assessment.

References

• Pollutants in Urban Waste Water and Sewage Sludge Priority Substances Daughter Directive, European Commission.