Analysis of Multiclass Multiresidue Pesticides in Milk Using Agilent Captiva EMR—Lipid with LC/MS/MS and GC/MS/MS

Importance of the Topic

Milk is a nutritionally vital food, particularly for infants and children. The presence of pesticide residues poses health and regulatory concerns worldwide. Achieving reliable detection of diverse pesticide classes at low concentration levels is essential to ensure food safety and meet stringent maximum residue limits.

Objectives and Study Overview

This application note presents a unified workflow for analyzing 171 multiclass pesticide residues in milk. It combines Agilent QuEChERS extraction with Captiva EMR—Lipid cleanup, followed by analysis on LC/MS/MS and GC/MS/MS platforms. The goals were to improve sample preparation efficiency, reduce matrix interference, and achieve sensitive quantitation down to 1 ng/mL.

Methodology and Instrumentation

The sample preparation strategy includes:

• Extraction: QuEChERS EN 15662 method with acetonitrile and salts.
• Cleanup: Captiva EMR—Lipid 6 mL cartridges for selective lipid removal; secondary elution with 80:20 acetonitrile:water to maximize recoveries.
• Water removal for GC/MS/MS: anhydrous MgSO₄ salting out.

Instrumentation details:

• LC/MS/MS: Agilent 1290 Infinity II system coupled to a 6470A triple quadrupole with Jet Stream ESI; ZORBAX Eclipse Plus C18 column.
• GC/MS/MS: Agilent 8890 GC with 7010B triple quadrupole; HP-5ms UI capillary column.

Main Results and Discussion

• Matrix removal: Captiva EMR—Lipid achieved over 99% lipid elimination, outperforming C18 SPE and dSPE approaches and reducing background signals.
• Recovery and precision: 98% of the 171 pesticides showed recoveries between 60% and 120%, and over 95% had RSD ≤10% at spiking levels from 5 to 100 ng/mL.
• Sensitivity: Most compounds were quantifiable down to 1 ng/mL in milk.
• Workflow efficiency: The method introduced 2.5 to 3.1-fold dilution steps while maintaining high performance across two instrumental platforms.

Benefits and Practical Applications

The described workflow delivers:

• Streamlined sample preparation with minimal handling time.
• Robust cleanup for fatty matrices, reducing instrument maintenance.
• High-throughput screening for regulatory compliance and quality control in dairy industries.

Future Trends and Potential Applications

• Extension to other lipid-rich matrices, such as cheese and butter.
• Integration with high-resolution mass spectrometry for non-targeted screening.
• Automation of the EMR—Lipid cleanup step for higher laboratory throughput.
• Development of multi-matrix approaches leveraging unified sample preparation.

Conclusion

The combination of QuEChERS extraction and Captiva EMR—Lipid cleanup provides an efficient, reliable protocol for multiclass pesticide residue analysis in milk. Both LC/MS/MS and GC/MS/MS platforms deliver precise quantitation with excellent recovery and reproducibility, supporting stringent food safety monitoring.

Reference

1. Abou Donia, M. A. et al. Chemical Composition of Raw Milk and the Accumulation of Pesticide Residues in Milk Products. Global Veterinaria 2010, 4(1), 6.
2. GB 2763-2019 National Food Safety Standard—Maximum Residue Limits for Pesticides in Food.
3. Yang, X. Analysis of Formamidine Pesticides and Metabolites in Pork and Porcine Liver Using Agilent Captiva EMR—Lipid and LC/MS/MS. Agilent Technologies application note, 5994-0357EN, 2019.
4. Zhao, L. Determination of Multiclass, Multiresidue Pesticides in Olive Oils by Captiva EMR—Lipid Cleanup and GC/MS/MS. Agilent Technologies application note, 5994-0405EN, 2018.