Automated determination of 3-monochloropropanediol, glycidol and their esters in foodstuffs with GC-MS/MS

Importance of the Topic

Industrial food processing at elevated temperatures and during oil refining can generate 3-monochloropropanediol (3-MCPD) and glycidol fatty acid esters, which release free 3-MCPD and glycidol upon digestion. These free compounds are classified as potential carcinogens, prompting regulatory bodies such as EFSA to establish a Tolerable Daily Intake (TDI) of 2 µg/kg body weight. Reliable analytical methods are therefore vital for food safety monitoring and regulatory compliance.

Objectives and Study Overview

This work focuses on automating the ISO 18636-1 protocol to determine total bound 3-MCPD and glycidol esters in fats, oils, and fatty food matrices. Two assays are performed: Assay A quantifies the sum of bound 3-MCPD and glycidol, while Assay B measures bound 3-MCPD alone. Glycidol content is calculated via a transformation factor derived from the difference between assays.

Methodology and Instrumentation

The sample preparation workflow includes: sample dissolution, base-catalyzed ester cleavage, reaction quenching with salt solutions (NaCl for Assay A; NaBr for Assay B), organic extraction with n-hexane and diethyl ether/ethyl acetate, dehydration, derivatization using phenylboronic acid, and final GC-MS/MS analysis. Automation is achieved using a CHRONECT Robotic dual-head system coupled directly to the GC-MS/MS.

Used Instrumentation

• CHRONECT Robotic Dual-Head Workstation for automated sample handling
• Gas Chromatograph coupled with Tandem Mass Spectrometer (GC-MS/MS)
• Automated solvent modules: dilutor, agitator, wash station, vortex mixers
• Temperature-controlled Peltier stack and syringe tool modules

Key Results and Discussion

Validation across various matrices (fats/oils, biscuits, chocolate, milk powder) showed limits of quantification near 0.05 mg/kg, linearity with RSDs below 5%, recoveries between 88% and 102%, and repeatability under 6% RSD. Expanded measurement uncertainties (k=2) ranged from 20% to 30%, confirming the method’s sensitivity, precision, and robustness even under fully automated conditions.

Benefits and Practical Applications

• Significant reduction in manual labor and hands-on time
• Increased sample throughput and faster turnaround
• Minimized contamination risk through closed-tube automation
• Compliance with regulatory maximum levels in diverse food matrices

Future Trends and Potential Applications

Future developments may include integration with advanced data analytics and machine learning for trend prediction, extension of the automated platform to other process contaminants, miniaturization of robotic components, and real-time online monitoring capabilities to support proactive quality control.

Conclusion

The fully automated adaptation of the ISO 18636-1 method for GC-MS/MS analysis delivers a robust, high-throughput solution for quantifying 3-MCPD and glycidol esters in food. It enhances analytical efficiency, reduces contamination risk, and provides accurate data for regulatory compliance and consumer safety.

References

• EFSA Journal 2016;14(5):4426. Risks for human health related to the presence of 3- and 2-monochloropropanediol (MCPD), and their fatty acid esters, and glycidyl fatty acid esters in food. EFSA Panel on Contaminants in the Food Chain (CONTAM).