Determination of Chemical Contaminants in Indian prawns by Fast GC-MS/MS using modifed QuEChERS as an extraction method

Importance of the Topic

Persistent organic pollutants and various pesticide residues are widely found in aquatic environments and tend to accumulate in fatty tissues of marine species such as prawns. European Union maximum residue limits (EU-MRLs) for these contaminants are stringent (typically 10 ng/g), driving the need for sensitive, high-throughput analytical methods in exporting countries like India.

Study Objectives and Overview

This work aimed to develop and validate a single, fast multi-residue method for 95 analytes—including organophosphorus, synthetic pyrethroids, organochlorines, polycyclic aromatic hydrocarbons and PCBs—in Fenneropenaeus indicus (Indian prawns). The method combines a modified QuEChERS extraction with fast GC-MS/MS on a Shimadzu GCMS-TQ8040.

Used Instrumentation

• Shimadzu GCMS-TQ8040 triple quadrupole system
• Rxi-5Sil MS micro-bore column (10 m × 0.10 mm × 0.10 µm)
• Helium carrier gas, split injection (ratio 4:1), 1 µL injection volume
• MRM acquisition with Smart MRM technology and ASSP for high sensitivity

Methodology

The sample preparation workflow was:

• Homogenize finely ground prawn tissue with water; equilibrate 30 min
• Add acidified acetonitrile with buffering salts; shake and vortex
• Centrifuge (6000 rpm, 5 min) and collect acetonitrile layer
• dSPE clean-up with MgSO4 and PSA; centrifuge again
• SPE clean-up using C18 cartridge; collect eluate
• Filter final extract (0.2 µm PTFE) before GC-MS/MS analysis

Results and Discussion

The optimized fast-GC temperature program and micro-bore column reduced total run time by 2.5× (to 18 min) while maintaining peak shape and data density (20,000 u/s). Smart MRM automated the selection of optimal transitions. Method performance in prawn matrix:

• Recoveries: 60 compounds at 5 ng/mL and 10 compounds at 10 ng/mL fell between 70–120%
• Repeatability (RSDr) < 20% for 91 analytes at 5 ng/mL; remaining 4 met criteria at 10 ng/mL
• Effective removal of matrix interferences demonstrated by clear MRM chromatograms

Benefits and Practical Applications

The method meets EU-MRL requirements for over 80% of tested analytes and is suitable for routine QA/QC in seafood export testing. High throughput and automated MRM optimization streamline multi-residue analysis in complex matrices.

Future Trends and Opportunities

Potential developments include:

• Further miniaturization and automation of sample prep (e.g., QuEChERS robotics)
• Integration of AI-driven MRM optimization for new compounds
• Expansion to other seafood and environmental matrices
• Coupling with high-resolution MS for non-target screening

Conclusion

A fast GC-MS/MS workflow combined with a modified QuEChERS extraction provides reliable, sensitive quantitation of diverse contaminants in prawns. This approach supports compliance with international residue limits and enhances laboratory throughput for food safety monitoring.

References

No formal reference list was provided in the original document.