Determination of Chemical Contaminants in Marine Shellfish using the Agilent 7000 Triple Quadrupole GC/MS System

Summary: Determination of Chemical Contaminants in Marine Shellfish

Importance of the Topic

Monitoring chemical pollutants in marine shellfish is critical for protecting public health, ensuring compliance with international directives (OSPAR, EC Dangerous Substance and Shellfish Hygiene Directives) and supporting environmental assessment programs such as the UK Clean Seas Environmental Monitoring Program.

Study Objectives and Overview

This application note details the development and validation of a rapid sample preparation and GC/MS/MS protocol for simultaneous quantification of organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in mussel tissue, achieving detection limits specified by regulatory standards.

Methodology

The workflow combines a modified QuEChERS extraction with acetonitrile and 1% acetic acid, salting out, freeze‐out clean-up and silica SPE fractionation. Sequential solvent exchanges (dichloromethane, hexane) and evaporation steps concentrate analytes into a final 0.5 mL extract.

Instrumentation

An Agilent 7890A GC was fitted with a CO2-cooled multimode inlet (MMI) for cold splitless or solvent-vent injections and a 15 m DB-5MSUI column connected via a restrictor and a post-column backflush tee to an Agilent 7000B triple quadrupole MS. The MS operated in EI mode using multiple reaction monitoring (MRM) transitions, and retention time locking was applied using PCB 118.

Main Results and Discussion

• Chromatographic separation of 51 target analytes was achieved within a 20 min run, with clear resolution of isomeric HCHs, PAHs and PCB congeners.
• Calibration over 0.4–200 pg/µL yielded correlation coefficients (R²) above 0.999 for all compounds.
• Limit of detection met regulatory thresholds: 0.1 µg/kg for OCPs and PCBs, 0.5–1.0 µg/kg for PAHs.
• Spike recoveries in mussel tissue ranged from 85 % to 124 % with relative standard deviations below 16 %.
• Analysis of incurred mussel samples confirmed method applicability, detecting HCH isomers, PAHs (fluoranthene, pyrene) and PCB 180 at environmental levels.

Benefits and Practical Applications

The combined QuEChERS-GC/MS/MS approach offers a streamlined, high-throughput workflow with robust cleanup and minimal matrix interference, suitable for routine monitoring in environmental and food safety laboratories.

Future Trends and Possibilities

Advances may include automated QuEChERS platforms, coupling to high-resolution mass spectrometry for non-target screening, expansion to emerging contaminants, and further minimization of solvent use for greener analytical practices.

Conclusion

The validated method meets Clean Seas Program requirements, delivering reproducible, sensitive quantification of OCPs, PAHs and PCBs in mussel tissue. It provides a reliable tool for regulatory monitoring and environmental studies.

References

• Clean Seas Environmental Monitoring Program – GREEN BOOK, Marine Assessment and Review Group, UK.
• Hajslova J. et al., Rapid sample preparation for PCBs, PBDEs and PAHs in fish, accessed www.xcdtech.com, 2011.
• Rashid A. et al., Simple extraction/cleanup for organochlorine pesticides in soil by GC-MS/MS, Journal of Chromatography A, 1217 (2010) 2933–2939.
• Agilent application note 5990-3367EN, Improving GC-MS Robustness and Cycle Times with Capillary Flow Technology and Backflush, 2009.