Detection of Mycotoxins in Corn Meal Extract Using Automated Online Sample Preparation with LC-MS/MS

Significance of the topic

The presence of mycotoxins in cereal products such as corn meal threatens food safety and human health. Monitoring these toxins at low concentrations is essential to comply with regulatory standards and to ensure consumer protection. Advances in analytical methods that reduce manual steps and increase throughput are highly valuable in routine testing laboratories.

Objectives and Study Overview

This work aims to establish an automated online sample preparation workflow combined with LC MS MS that can detect and quantify multiple mycotoxins in corn meal extract with improved speed and sensitivity. By integrating a TurboFlow based system with a triple quadrupole mass spectrometer, the method seeks to cut assay time and boost sample throughput.

Materials and Methods

The sample preparation begins by extracting 5 g of corn meal with 70 percent methanol followed by sonication and overnight settling. After centrifugation the supernatant serves as the basis for matrix calibrators and quality controls corresponding to 0.2 g of sample per milliliter. Two LC MS MS methods were implemented:

• Method A uses positive electrospray ionization to analyze eight mycotoxins including aflatoxins B1 B2 G1 G2 zearalenone ochratoxin A and fumonisins B1 B2
• Method B employs negative electrospray ionization for deoxynivalenol nivalenol and 3 acetyl deoxynivalenol

Instrumentation Used

Key equipment includes:

• Thermo Scientific Transcend TLX 1 automated online sample preparation system with TurboFlow technology
• Thermo Scientific TSQ Vantage triple stage quadrupole mass spectrometer with heated electrospray ionization source
• TurboFlow Cyclone P and Hypersil GOLD analytical columns
• Thermo Scientific Aria operating software for method control

Main Results and Discussion

Chromatograms demonstrate clear separation of all targeted toxins in both solvent and corn matrix with minimal carry over. Matrix matched calibration showed linear response R2 greater than 0.99 for most analytes. Limits of quantitation ranged from sub nanogram per gram levels for aflatoxins to 50 ng per gram for zearalenone meeting European regulatory requirements. Enhanced signals for fumonisins B1 and B2 indicate ionization effects due to matrix constituents suggesting the future use of isotope labeled standards for compensation.

Benefits and Practical Applications

The automated workflow eliminates labor intensive manual clean up steps enhancing method robustness and reproducibility. The integration of online sample preparation with LC MS MS significantly reduces total assay time and supports high throughput testing in food safety and quality control laboratories.

Future Trends and Possibilities

Expanding this protocol to diverse food matrices will further demonstrate its versatility. Multiplexed channels on the Transcend TLX 2 or 4 systems can improve sample throughput. Increasing injection volumes enabled by TurboFlow columns may lower detection limits. Incorporation of isotopically labeled internal standards will enhance quantitation accuracy in complex matrices.

Conclusion

An automated LC MS MS approach for the simultaneous detection of multiple mycotoxins in corn meal has been successfully developed. The method combines online sample preparation with TurboFlow technology and triple quadrupole detection to achieve sensitive quantitation, streamlined workflow, and compliance with regulatory limits.

References

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