Analysis of Fipronil and Metabolites in Chicken and Eggs Using Agilent QuEChERS Kit Followed with Agilent Bond Elut EMR—Lipid Cleanup by LC/MS/MS

Significance of the Topic

The detection of fipronil and its metabolites in poultry products is critical for food safety and public health. Recent contamination events have underscored the need for rapid, reliable analytical workflows to ensure compliance with regulatory limits and protect consumers.

Objectives and Study Overview

This study aimed to develop and validate a streamlined method for the quantitative analysis of fipronil, fipronil sulfone, fipronil sulfoxide, and fipronil desulfinyl in chicken tissue and egg matrices. The focus was on combining efficient sample cleanup with sensitive LC/MS/MS detection to address high-throughput testing demands.

Methodology and Used Instrumentation

Sample Preparation

• Weighed 5 g of homogenized chicken or egg sample.
• Hydrated with water, followed by acetonitrile extraction using Agilent Bond Elut EN QuEChERS salts.
• Performed lipid removal using Agilent Bond Elut EMR—Lipid dSPE and polish pouches, including drying salts.
• Filtered the final extract through a 0.2 µm nylon syringe filter.

Used Instrumentation

• Agilent 1290 Infinity II UHPLC system with binary pump, autosampler, and thermostatted column compartment.
• Agilent InfinityLab Poroshell 120 EC-C18 column (75 × 3 mm, 2.7 µm).
• Agilent G6470 triple quadrupole MS with JetStream electrospray ionization.
• MassHunter workstation for data acquisition and processing.

Chromatographic Conditions

• Mobile phases: water (A) and methanol (B).
• Gradient from 60% to 98% B over 5 min, total runtime 9.5 min including reequilibration.
• Flow rate of 0.4 mL/min, column temperature 40 °C, injection volume 5 µL.

MS/MS Conditions

• Negative ion mode, MRM transitions optimized for each analyte.
• Gas temperature 250 °C, gas flow 7 L/min, capillary voltage 0 V in positive and 3,500 V in negative mode.

Main Results and Discussion

Recovery and precision tests at spiking levels of 1, 5, and 20 µg/kg showed recoveries between 91% and 102% with RSDs below 6.3% for both chicken and eggs. Calibration curves exhibited linearity with R2 values >0.995. Lipid removal efficiency was demonstrated by significant reduction of phospholipid signals when using EMR—Lipid cleanup compared to conventional C18/PSA methods, leading to cleaner baselines and improved analyte response.

Benefits and Practical Applications

• High throughput: simplified workflow allows processing multiple samples per day.
• Robust cleanup: EMR—Lipid technology efficiently removes matrix interferences without extensive labor.
• Regulatory compliance: sensitive and reproducible detection meets food safety monitoring requirements.
• Versatility: adaptable to other fatty food matrices beyond poultry.

Future Trends and Opportunities

Emerging directions include miniaturization of sample preparation, automation of QuEChERS workflows, and extension to multiplex screening of additional pesticide residues. Integration with high-resolution mass spectrometry could further enhance specificity for complex matrices.

Conclusion

The presented method combining Agilent QuEChERS extraction and Bond Elut EMR—Lipid cleanup with LC/MS/MS provides a reliable, efficient, and reproducible solution for quantifying fipronil and its metabolites in chicken and egg samples. It addresses critical needs for food safety laboratories facing contamination crises.