Determination of Multiple Mycotoxins in Grain Using a QuEChERS Sample Preparation Approach and LC-MS/MS Detection

Importance of the Topic

Mycotoxins are toxic secondary metabolites produced by fungi on grains and are resistant to heat and processing, posing health risks at low levels. Rapid and comprehensive analysis of multiple mycotoxin residues in grain-based foods is vital for food safety monitoring and regulatory compliance.

Study Objectives and Overview

This study aimed to develop a fast, simple, and cost-effective QuEChERS sample preparation approach coupled with LC-MS/MS using a Thermo Scientific Accucore aQ column and TSQ Vantage triple quadrupole mass spectrometer to detect 16 mycotoxins in cereals. Key objectives:

• Optimize extraction and cleanup for a broad polarity range of mycotoxins.
• Achieve efficient chromatographic separation within a short run time.
• Validate method performance in terms of linearity, sensitivity, accuracy, and precision.

Methodology

A QuEChERS protocol was employed: 5 g of hydrated cereal sample was extracted with acidified acetonitrile and unbuffered salts, followed by dispersive SPE cleanup using PSA and C18 sorbents. After evaporation and reconstitution in 50:50 methanol/water, samples were filtered prior to analysis.

Used Instrumentation

• HPLC system: Thermo Scientific Dionex UltiMate 3000.
• Column: Thermo Scientific Accucore aQ, 100×2.1 mm, 2.6 µm (guard column: 10×2.1 mm).
• Mass spectrometer: Thermo Scientific TSQ Vantage triple quadrupole with APCI+/- and rapid polarity switching.
• Data processing: Thermo Scientific Xcalibur software with 1/X weighting.

Main Results and Discussion

• Chromatographic separation of 16 mycotoxins, including α- and β-zearalanol, was completed in 13 min with baseline resolution.
• Matrix-matched calibration curves showed excellent linearity (R² > 0.995) over 10–200 µg/kg, with signal-to-noise ratios > 10 at the lowest level.
• LOQs were ≤ 10 µg/kg for all analytes. Recoveries ranged from 67% (nivalenol) to 107% with RSD ≤ 11% at 20 and 100 µg/kg fortification levels.
• First 1.5 min and last 4 min of the run were diverted to waste to minimize matrix effects and source contamination.
• No significant analyte carryover was observed.

Benefits and Practical Applications of the Method

• Rapid analysis with a total run time of 17 min, including equilibration.
• Simple QuEChERS workflow minimizes solvent consumption and costs.
• High sensitivity and broad coverage of 16 relevant mycotoxins in a single injection.
• Robust performance suitable for routine monitoring in quality control and regulatory laboratories.

Future Trends and Potential Applications

• Extension to high-resolution mass spectrometry for non-targeted mycotoxin screening.
• Automation and high-throughput setups to increase sample capacity.
• Integration with online cleanup modules to further reduce manual steps.
• Application to other complex food matrices beyond cereals.

Conclusion

The developed QuEChERS-LC-MS/MS method provides a fast, sensitive, and reliable approach for simultaneous determination of multiple mycotoxins in grain-based foods, meeting the demands of modern food safety testing.

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