Mark W. Collison, Ph. D., Director, Analytical Chemistry

Research Division

Archer Daniels Midland Company and Chair of the Uniform Methods Committee

Current status of MCPD and Glycidol Analysis in Oils

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2012 -2013 AOCS Indirect Methods Collaborative

• Methods were requested at the 2012 AOCS meeting

• ADM prepared test samples spiked with known amounts of 3-MCPD esters and glycidyl esters

• Three indirect methods were submitted

• AOCS also requested comparison with direct methods (Cd 28-10 and other direct LCMS methods)

• 20 Laboratories participated in the collaborative study. 31 sets of data were submitted using indirect methods

• 8 sets of data were submitted using direct methods

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AOCS Indirect Method 1 – 12 labs • 2- and 3-MCPD Fatty Acid Esters and Glycidyl Fatty

Acid Esters in Edible Oils and Fats Based on Acid Transesterification

• Determines glycidol by pre-reaction with bromide

• 16 hour incubation at 40 °C to convert MCPD esters to MCPD

• Determines both 2- and 3-MCPD

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AOCS Indirect Method 2 – 10 labs • 2- and 3-MCPD Fatty Acid Esters and Glycidyl Fatty

Acid Esters in Edible Oils and Fats Based on Cold

(-22 °C) Base Transesterification

• Corrects for artifacts by calculation of standards converted

• 16 hour incubation at -22 °C to convert MCPD esters to MCPD

• Determines both 2- and 3-MCPD

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AOCS Indirect Method 3 – 9 labs • 2- and 3-MCPD fatty acid esters and glycidyl fatty

acid esters in edible oils and fats based on dilute base transesterification

• Determines glycidol by subtraction of the analysis in the presence and absence of chloride.

• Assumes that glycidol is the only precursor that produces artifacts

• Assumes that no chloride is present in the sample.

• Short incubation to convert MCPD esters to MCPD and glycidyl esters to MCPD

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Direct Methods: Cd 28-10 – 4 labs (GE only)

Joint AOCS/JOCS Official Method Cd 28-10

Approved 2012

Glycidyl Fatty Acid Esters in Edible Oils

DEFINITION

This method is used for the determination of

glycidyl (glycidol) fatty acid esters (GEs) in

edible oils using double solid-phase extraction

(SPE) and liquid chromatography—mass

spectrometry (LC-MS).

SCOPE

Applicable for the determination of glycidyl fatty

acid esters (GEs) in commercial vegetable oils

and fats.

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Direct Methods for MCPD Esters and Glycidyl Esters

Each direct LCMS method was used in only one lab.

• TOF-MS method – no pre-extraction

LC/MS/MS with sample pre-extraction

• Wilm 2012

• Yamazaki

• Tadmen

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• Very high analyte concentrations

• Test sample for direct methods

• RBD Canola Oil spiked with 7 3-MCPD monoesters at ~7 ppm each, 28 3-MCPD diesters at 4-8 ppm each and 7 glycidyl esters at ~5 ppm each

Collaborative Results: Sample 1

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Collaborative Results: Sample 2 • RBD Canola Oil spiked with

5 glycidyl esters at ~1.5 ppm each

• All indirect methods were reproducible for glycidol analysis

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Collaborative Results: Sample 3 • RBD Canola Oil spiked with

15 3-MCPD diesters at 1 – 3 ppm each

• All indirect methods were acceptable for 3-MCPD analysis

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Collaborative Results: Sample 4 • High level sample

• RBD Canola Oil spiked with 15 3-MCPD diesters at 4-8 ppm each and 5 glycidyl esters at ~5 ppm each

• All indirect methods were acceptable for both glycidol and MCPD analyses

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Collaborative Results: Sample 5 • RBD Canola Blank used to

make samples 1-4

• Variable results between methods for both MCPD and glycidol at these low contaminant levels.

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Collaborative Results: Sample 6 • Palm oil sample, not spiked.

• Low MCPD concentrations and moderate glycidol concentration.

• All indirect methods were acceptable

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Collaborative Results: Sample 7 • Training sample. Palm oil

(spiked levels from previous study)

• All indirect methods were acceptable and close to the direct methods

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Direct LCMS Methods for Glycidyl Esters Glycidol by LCMS analysis of glycidyl esters was good in most cases.

Most LCMS methods for glycidol were in fair agreement with indirect methods and with the expected values for spiked samples.

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Direct LCMS Methods for MCPD Note: Direct LCMS methods did not resolve 2-MCPD from 3-MCPD. Samples were spiked with only 3-MCPD.

Most LCMS methods for MCPD were in fair agreement with indirect methods and with the expected values for spiked samples.

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Summary • All 3 of the indirect methods tested gave comparable results

• In general the direct methods agreed with the indirect methods.

• Methods, either direct or indirect, did not give reliable results if total MCPD concentrations or glycidol concentrations were below ~1 ppm.