ISO 18363-4:2021

Overview

ISO 18363-4:2021 specifies a rapid, single-assay method for the simultaneous determination of ester-bound 2‑MCPD, 3‑MCPD and glycidol in animal and vegetable fats and oils. The procedure uses a fast alkaline transesterification (alkaline-catalysed ester cleavage), followed by derivatization of released analytes with phenylboronic acid (PBA) and quantification by GC‑MS/MS. The method corrects for method-induced artefacts (overestimation of glycidol) by using isotopically labelled ester internal standards. Applicable to solid and liquid fats and oils; some matrices (milk products, infant formula, emulsifiers, free fatty acids) are explicitly excluded.

Key topics and technical requirements

• Purpose: simultaneous measurement of 2‑MCPD esters, 3‑MCPD esters and glycidyl esters (glycidol) in a single, rapid assay.
• Principle steps: alkaline ester cleavage → derivatization with phenylboronic acid (PBA) → GC‑MS/MS analysis.
• Artefact correction: addition of isotopically labelled ester-bound 3‑MCPD and glycidyl internal standards to quantify and correct glycidol overestimation caused by MCPD-induced conversion.
• Instrumentation: GC‑MS/MS is required to unambiguously detect isotopically labelled mono-brominated derivatives and target analytes.
• Sensitivity: Limit of quantification (LOQ): 0.1 mg/kg; Limit of detection (LOD): 0.03 mg/kg for all three analytes.
• Matrices: validated for refined and unrefined vegetable oils and fats; applicable to animal fats and used frying oils and fats (these were not included in the validation study).
• Exclusions: milk and milk products (and their fats), infant formulas, emulsifiers, free fatty acids and other derived matrices.
• Quality control aspects: calibration curve preparation, use of isotopic internal standards, chromatographic confirmation and method precision/reproducibility are addressed in the standard.

Applications and who uses it

• Food safety and regulatory laboratories assessing compliance with limits for MCPD and glycidyl esters in edible oils and fats.
• Oil refiners and food manufacturers performing routine quality control on refined/unrefined oils, frying oils and fat-based ingredients.
• Contract testing and analytical service labs offering lipid contaminant testing using GC‑MS/MS.
• Research labs studying formation pathways of MCPDs and glycidyl esters during refining and thermal processing.

Practical benefits include a faster single-sample workflow for three analytes, correction for method-induced artefacts, and robust LOQ/LOD suitable for regulatory monitoring.

Related standards

• Other parts of the ISO 18363 series (ISO 18363‑1, ‑2, ‑3) describe alternative procedures (differential, slow alkaline, acidic conversions) for MCPD and glycidol determination and may be selected based on matrix, validation needs and instrument availability.