Determination of Mycotoxins in Peanuts With Enhanced Matrix Removal—Lipid by LC/MS/MS

Significance of the Topic

Mycotoxins in peanuts represent a critical food safety concern due to their toxic effects on humans and animals. Accurate and sensitive analytical methods are essential to monitor and control these contaminants in high-fat matrices such as peanuts, ensuring compliance with regulatory limits and protecting public health.

Objectives and Study Overview

This application note describes a robust LC/MS/MS method for the quantitative determination of 12 mycotoxins in peanuts. The primary goals were to achieve low limits of quantification below regulated maximum residue levels, demonstrate effective removal of lipid interferences, and validate method performance in terms of linearity, recovery, and precision.

Methodology and Instrumentation

The sample preparation involved two key cleanup steps:

• QuEChERS extraction using Agilent Bond Elut QuEChERS EN salts to extract mycotoxins from a 5 g peanut sample with acidified water and acetonitrile.
• Dispersive SPE cleanup with Agilent Bond Elut EMR–Lipid sorbent and subsequent MgSO₄ polishing to remove co-extracted lipids.

The purified extracts were analyzed by LC/MS/MS using an Agilent 1290 Infinity LC coupled to an Agilent 6460 Triple Quadrupole MS. Separation was achieved on a ZORBAX Eclipse Plus C18 column (2.1 × 50 mm, 1.8 µm) with a water/methanol gradient containing 0.1 % formic acid. MS acquisition employed positive-mode MRM transitions optimized for each mycotoxin.

Main Results and Discussion

Matrix effects assessment showed that EMR–Lipid cleanup effectively removed lipids, minimizing ion suppression/enhancement to below 20 % for all compounds. Calibration curves were linear across 0.15–500 ng/mL with R² > 0.998. Experimental LOQs ranged from 0.15 to 0.75 ng/mL, well below regulatory limits (e.g., 8 µg/kg for aflatoxin B1). Recovery studies at low, mid, and high spike levels (4–100 ng/g) yielded 80–110 % recoveries with RSDs < 10 %, meeting international validation criteria.

Benefits and Practical Applications

This combined QuEChERS–EMR approach offers:

• Efficient lipid removal leading to improved chromatographic performance and instrument uptime.
• High sensitivity suitable for compliance monitoring in peanuts and other fatty commodities.
• Streamlined workflow adaptable to routine QA/QC labs and regulatory testing.

Future Trends and Applications

Advances may include integration with high-resolution mass spectrometry for non-target screening, miniaturized sample preparation to reduce solvent use, and automated platforms for higher throughput. Expansion to other fat-rich matrices and multi-class contaminant panels will broaden applicability.

Conclusion

The developed LC/MS/MS method combining QuEChERS extraction and EMR–Lipid dispersive SPE effectively quantifies 12 mycotoxins in peanut with excellent sensitivity, accuracy, and precision. Minimal matrix effects and robust performance support its use for routine mycotoxin monitoring in high-fat samples.

References

1. GB 2761–2011 Maximum Residue Limits for Mycotoxins in Food.
2. Commission Regulation (EC) No 1881/2006, Setting Maximum Levels for Contaminants in Foodstuffs.
3. Hussein HS, Brasel JM. Toxicity, Metabolism, and Impact of Mycotoxins on Humans and Animals. Toxicology. 2001;167:101–134.
4. Liu Y, et al. Simultaneous Determination of 26 Mycotoxins in Sesame Butter Using Modified QuEChERS with UHPLC-ESI/MS. Agilent Technologies Application Note, 2015.
5. Zhao L, Lucas D. Multiresidue Analysis of Veterinary Drugs in Bovine Liver by LC/MS/MS. Agilent Technologies Application Note, 2015.