Rapid LC-MS/MS Method for the Analysis of Fipronil and Amitraz Insecticides and Associated Metabolites in Egg and Other Poultry Products

Significance of the Topic

Egg contamination by fipronil in 2017 led to international recalls affecting consumer health and food safety. A robust, rapid analytical method for insecticide residues in poultry products is critical to ensure compliance with regulatory limits and maintain public trust.

Study Objectives and Overview

This work describes a fast, sensitive LC-MS/MS assay for simultaneous detection and quantitation of fipronil, amitraz and their metabolites in eggs and other poultry matrices. The goal is to meet EU maximum residue limits (5 µg/kg) and provide a single-method solution for quality control laboratories.

Sample Preparation and Methodology

A modified QuEChERS protocol was applied to extract analytes from homogenized egg and poultry samples. Key steps include:

• Extraction with acetonitrile and salting-out using MgSO4, NaCl and buffering salts
• Post-extraction cleanup via calcium chloride treatment
• Dilution of final extract prior to LC-MS/MS analysis

Instrumentation

The assay employed:

• Chromatography: Phenomenex Kinetex Polar C18 column (100 x 2.1 mm, 2.6 μm) with water/methanol gradient
• LC system: SCIEX Exion LC
• Mass spectrometry: SCIEX Triple Quad 6500+ with electrospray ionization and fast polarity switching
• Detection mode: Scheduled multiple reaction monitoring (MRM)

Main Results and Discussion

The method achieved limits of detection and quantitation below the EU MRL of 5 µg/kg for all target compounds. Calibration curves were linear from 0.5 to 50 ppb (R² > 0.99). Reproducibility at the MRL level showed relative standard deviations below 11%. Matrix effects from egg, egg powder, meat and fat were consistent and compensated by isotopically labeled internal standards.

Benefits and Practical Applications

This single-run assay offers:

• High throughput with a 7-minute runtime per injection
• Accurate quantitation at regulatory thresholds
• Applicability to diverse poultry matrices
• Simplified workflow reducing sample preparation time

Future Trends and Opportunities

Advancements may include integration with high-resolution accurate mass systems for non-targeted screening, automation of QuEChERS workflows, and expansion to additional pesticide classes. Cloud-based data processing and AI-driven interpretation could further streamline residue analysis.

Conclusion

The presented LC-MS/MS method provides a reliable, rapid solution for monitoring fipronil, amitraz and related metabolites in egg and poultry products. It meets EU regulatory requirements with high sensitivity, reproducibility and throughput, making it suitable for routine food safety testing.

References

• Regulation (EC) No. 396/2005 on maximum residue limits of pesticides in food
• EFSA Acute Reference Dose for fipronil: 0.009 mg/kg body weight