A Fully Automated Method For MCPD – and GE- Esters And The Importance of Glass Quality Of the used Autosampler Vials

Importance of the Topic

Monochloropropanediol esters (MCPDe) and glycidyl esters (GE) form during oil refining and pose safety concerns in food products. Precise quantification of these compounds at trace levels is essential for regulatory compliance and consumer protection. Glass vial quality plays a crucial role in automated analysis as adsorption of polar analytes onto silanol sites can reduce recovery and compromise detection limits.

Study Objectives and Overview

This work aims to deliver a fully automated method for simultaneous determination of MCPDe and GE in edible oils. By combining sample preparation, derivatization, injection, and data processing in a single robotic sequence, the approach targets high throughput, reproducibility, and minimized manual intervention.

Methodology and Instrumentation

A Thermo Scientific TriPlus RSH autosampler equipped with a heated tray and backflush split/splitless injector automates sample handling. Oils are weighed into Chromacol GOLD grade inert glass vials to prevent analyte loss. The workflow includes:

• Transesterification and derivatization steps in vial using NaOCH3/MeOH and acidified NaBr
• Back-extraction with iso-octane to isolate analyte derivatives
• Analysis by GC–MS/MS on a Trace 1310 GC coupled to TSQ 9000 detector
• Chromeleon software for data review, calibration, QC monitoring, and LIMS export

The GC oven program ramps from 70 °C to 350 °C with splitless injection. MS/MS transitions are optimized for 3-MCPD, 2-MCPD, 3-MBPD, and glycidol derivatives with stable isotope internal standards for correction.

Main Results and Discussion

The method achieved detection limits of 10 µg/kg for 3-MCPD and 18.5 µg/kg for glycidol, with quantification limits at 15 and 41 µg/kg respectively. Use of high-quality low-expansion glass vials reduced analyte loss and improved precision. Automated blank and spike trials yielded consistent recoveries above 90 % and calibration linearity across 1–500 ppb.

Benefits and Practical Applications

• Reduction of manual labor to sample weighing only
• Single-injection analysis for full MCPDe and GE profile
• Short reaction and analysis time enabling up to 40 samples per day continuously
• Integrated QC, calibration, and data processing in one software environment

Future Trends and Opportunities

Advancements may include coupling the workflow with high-resolution MS for non-target screening, extending the method to other polar lipid contaminants, and applying machine learning for real-time data quality assessment. Improvements in vial coatings and automation platforms can further enhance sensitivity and throughput.

Conclusion

The fully automated MCPDe and GE analysis workflow offers reliable, high-throughput quantification with minimal manual steps. Selection of inert, low-silanol glass vials is critical to achieving trace-level detection and consistent recoveries. The integrated system streamlines compliance with food safety regulations and supports large-scale monitoring programs.

Reference

1. R. Zwagerman, P. Overman, Eur. J. Lipid. Sci. Technol. 2016, 118, 997
2. AOCS Official Method 29b-13, approved 2013
3. R. Zwagerman, P. Overman, Eur. J. Lipid. Sci. Technol. 2019, 121, 1800395