Multi-residual quantitative analytical method for antibiotics in sea food by LC/MS/MS

Importance of the Topic

Seafood consumption presents a potential route for human exposure to veterinary antibiotics, contributing to antimicrobial resistance. Sensitive and multiplexed analytical methods are critical to monitor residue levels, ensure food safety and support environmental impact studies.

Objectives and Study Overview

This work aimed to establish and validate a rapid LC/MS/MS protocol for simultaneous quantification of seven antibiotic classes in shrimp. The target analytes include fluoroquinolones, sulfonamides, dyes, antihelminthics, nitroimidazoles, phenylbutazone and macrolides at regulatory relevant levels (sub-ppb to tens of ppb).

Methodology

Sample Preparation

• Homogenize shrimp tissue using a crushing mixer.
• Extract analytes with acidified acetonitrile under cold centrifugation (4 °C, 8000 rpm).
• Perform dispersive SPE cleanup and filter through 0.2 µm membranes.

Used Instrumentation

• UHPLC Nexera system with Shim-pack GIST Phenyl column (75 × 3.0 mm, 2 µm).
• Mobile phases: A – 2 mM ammonium formate with 0.002 percent formic acid in water; B – same buffer in methanol; gradient elution at 0.4 mL per minute.
• Shimadzu LCMS-8040 triple quadrupole MS with electrospray ionization, 15 000 u per second scan speed and 15 ms polarity switching.
• Scheduled MRM transitions optimized automatically for 40 target compounds.

Main Results and Discussion

• Calibration was linear (correlation coefficient above 0.99) over 0.5 to 50 ppb matrix-matched standards.
• Limits of quantitation ranged from 0.5 to 2 ppb for most antibiotics.
• Recoveries for the majority of analytes fell between 80 and 120 percent, satisfying typical regulatory criteria.

Benefits and Practical Applications

• High throughput analysis under 15 minutes per injection for complete multi-class screening.
• Efficient cleanup reduces solvent use and sample handling time.
• Suitable for routine monitoring in food safety laboratories, regulatory compliance and environmental surveillance.

Future Trends and Opportunities

Potential enhancements include:

• Integration of high resolution mass spectrometry for improved confirmation and broader contaminant coverage.
• Automated sample preparation workflows to further increase throughput and reproducibility.
• Expansion of analyte panels to emerging veterinary drugs and their metabolites.

Conclusion

The developed LC/MS/MS method provides a robust, sensitive and rapid platform for multi-residual antibiotic detection in seafood. It meets stringent recovery and quantitation requirements, facilitating effective monitoring of antibiotic residues and contributing to public health protection.

Reference

• Defoirdt T, Sorgeloos P, Bossier P Alternatives to Antibiotics for the Control of Bacterial Disease in Aquaculture Curr Opin Microbiol 2011 14 251–258