Determination of Multiclass Multiresidue Mycotoxins in Dry Corn Kernels and Soybeans

Importance of the Topic

Mycotoxins are toxic secondary metabolites produced by fungi that contaminate cereals and legumes. Their presence in dry corn kernels and soybeans poses serious health risks and economic losses. Regulatory agencies worldwide have established maximum residue limits, making reliable detection methods essential for food safety and quality assurance.

Objectives and Overview of the Study

• Develop and validate a multiclass multiresidue mycotoxin analysis in dry corn kernels and soybeans.
• Combine QuEChERS extraction with Agilent Captiva EMR Mycotoxins mixed-mode passthrough cleanup.
• Use LC/MS/MS detection on an Agilent 6475 triple quadrupole system.
• Benchmark against traditional solvent extraction and commercial SPE/dSPE workflows.

Used Methodology and Instrumentation

• Sample preparation: 2 g of ground sample extracted with acidified water and acetonitrile using a QuEChERS EN kit.
• Cleanup: Captiva EMR Mycotoxins 3 mL cartridge for mixed-mode removal of carbohydrates, organic acids, pigments, lipids and other coextractives.
• Dilution: 10× overall dilution, addition of five post-extraction isotopic internal standards.
• Chromatography: Agilent 1290 Infinity II LC with ZORBAX RRHD Eclipse Plus C18 column, gradient elution with water/formic acid/ammonium salts and methanol.
• Detection: Agilent 6475 triple quadrupole LC/MS/MS in dynamic MRM mode for 21 mycotoxins.

Main Results and Discussion

• Matrix cleanup: EMR passthrough achieved over 90 % removal of matrix interferences, outperforming SPE+dSPE and reducing instrument contamination.
• Recovery and precision: At three spiking levels, recoveries ranged 80–111 % with RSD < 12.5 % for all targets.
• Calibration: Neat calibration curves over 100–500× dynamic range, R2 > 0.99 with 1/x² weighting using five isotopic standards.
• Quantitation: ISTD-matched targets met 70–120 % accuracy and ≤ 20 % RSD; nonmatched targets generally met 65–135 % accuracy and ≤ 25 % RSD, highlighting the benefit of corresponding isotopic standards.

Benefits and Practical Applications of the Method

• Streamlined workflow with a single passthrough cleanup reduces hands-on time and potential sample loss.
• Enhanced sensitivity for labile mycotoxins such as fumonisins, ochratoxin A and cyclopiazonic acid.
• Applicable to routine food safety testing, QA/QC labs and high-throughput feed analysis.

Future Trends and Possibilities of Use

Expansion of isotopic internal standard availability will further improve accuracy. Integration with automated sample handling and adopting high-resolution MS may extend applicability to additional matrices, modified mycotoxins and emerging contaminants.

Conclusion

The validated QuEChERS extraction with EMR mixed-mode passthrough cleanup and LC/MS/MS detection provides a robust, efficient and sensitive platform for simultaneous analysis of 21 multiclass mycotoxins in complex dry feed matrices.

Reference

1. Bennett J.W.; Klich M. Mycotoxins. Clinical Microbiology Reviews. 2003;16:497–516.
2. U.S. FDA Compliance Program Manual, Chapter 7: Mycotoxins in Foods. CP 7307.001; 2016.
3. U.S. Department of Agriculture Laboratory Approval Program – Mycotoxins. LAP-PR-07; 2023.
4. European Commission Regulation 401/2006. Methods of Sampling and Analysis for Mycotoxins in Foodstuffs; 2006.
5. Zhang K. et al. Collaborative Study on Mycotoxins by SIDA and LC-MS/MS. J. Agric. Food Chem. 2017;65:7138–7152.
6. Gonzalez-Jartín J.M. et al. Multianalyte Mycotoxin Method in Milk by QuEChERS–UHPLC-MS/MS. Food Chem. 2021;356:129647.
7. Koesukwiwat U. et al. Modified QuEChERS for Mycotoxins in Rice. Food Chem. 2014;153:44–51.
8. Lucas D. Mycotoxin Analysis in Peanut Butter Using Captiva EMR–Lipid Cleanup and LC/MS/MS. Agilent application note 5994-0366EN; 2019.
9. Lucas D. Mycotoxin Analysis in Infant Formula Using Captiva EMR–Lipid Cleanup and LC/MS/MS. Agilent application note 5994-0365EN; 2019.