Automating the Accurate Transfer of Viscous Samples for the Completely Automated Extraction of Mycotoxins from Edible Oils

Significance of the Topic

Mycotoxins produced by toxigenic molds in edible oils pose a critical food safety risk due to their carcinogenic nature and strict regulatory limits. Accurate quantification at trace levels in viscous oil matrices is challenging and highly dependent on reliable sample introduction. Automating viscous sample handling and extraction ensures data integrity, enhances throughput, and reduces manual workload.

Objectives and Study Overview

The study aimed to demonstrate a fully automated workflow for liquid–liquid extraction of aflatoxins from edible oils and subsequent LC–MS/MS analysis using a single integrated platform. Key goals included validating a heated liquid syringe module for precise transfer of viscous samples and evaluating method performance across various oil types.

Methodology

The automated procedure, performed on the GERSTEL MPS roboticPRO sampler, comprised:

• Preheating 1.5 mL oil samples at 60°C, then transferring at 65°C using the Heated Liquid Syringe Module.
• Adding acetonitrile–formic acid (95:5, v/v), mixing, and centrifugation to extract mycotoxins.
• Partitioning with hexane to remove co-extracted lipids, mixing and centrifugation.
• Transferring the lower acetonitrile-rich layer, evaporating to dryness, and reconstituting in methanol–water (1:1).
• Direct injection or optional 0.2 µm filtration prior to LC–MS/MS analysis.

Instrumentation

The workflow integrated:

• GERSTEL MPS roboticPRO with Heated Liquid Syringe Module, heated agitator, CF-200 centrifuge, balance option, mVAP, quickMIX, and 5‐position dilutor.
• Agilent 1260 HPLC with Poroshell 120 EC-C18 column (3.0×50 mm, 2.7 µm) at 30°C.
• Agilent Ultivo triple quadrupole mass spectrometer with JetStream ESI source, positive mode detection.

Key Results and Discussion

• Viscous transfer accuracy improved with temperature: precision CV ≤0.12% for olive, sesame, flax, and sunflower oils; bias within ±5% of target volume.
• Automated extraction yielded precision ranging from 2.4% to 6.9% RSD for aflatoxins B1, B2, G1, and G2 in spiked olive oil replicates.
• Recovery rates averaged 87.9%–101% for B1, B2, G1 and up to 122% for G2 across all oil types, demonstrating method robustness.
• Calibration curves showed excellent linearity (R² ≥ 0.999) over targeted concentration ranges.

Benefits and Practical Applications

• Elimination of manual pipetting reduces analyst fatigue and human error.
• Integrated automation supports high throughput and consistent data quality in QA/QC and research laboratories.
• Approach is adaptable to other viscous matrices and extended to multianalyte screening workflows.

Future Trends and Opportunities

Automation in sample preparation is moving toward integrated systems with real-time monitoring and AI-driven optimization. Potential developments include:

• Expansion of heated syringe technology for a wider range of viscous and non‐Newtonian fluids.
• Enhanced connectivity with laboratory information management systems for seamless data tracking.
• Miniaturization and micro-extraction techniques to reduce solvent usage and improve sustainability.

Conclusion

The use of a heated liquid syringe module enabled precise automated transfer of viscous edible oils, successfully combined with fully automated mycotoxin extraction and LC–MS/MS analysis. This workflow delivers reproducible, high-quality results and can be extended to various viscous sample matrices in food safety and industrial analytics.

References

1. Bhat R, Reddy KRN. Challenges and issues concerning mycotoxin contamination in oil seeds and their edible oils: Updates from last decade. Food Chemistry. 2017;215:425–437.
2. Eom T, et al. Multiclass mycotoxin analysis in edible oils using a simple solvent extraction method and liquid chromatography with tandem mass spectrometry. Food Additives & Contaminants: Part A. 2017;34(11):2011–2022.