ISO 18363-2:2018

Overview - ISO 18363-2:2018 (MCPD and glycidol by GC/MS)

ISO 18363-2:2018 specifies a laboratory procedure for the parallel determination of 2‑MCPD, 3‑MCPD and glycidol in animal and vegetable fats and oils using gas chromatography/mass spectrometry (GC/MS). The method targets ester‑bound and any free forms of these contaminants by a controlled slow alkaline transesterification that releases the analytes, converts glycidol to a stable brominated derivative (3‑MBPD), and derivatises free diols with phenylboronic acid (PBA) prior to GC/MS analysis. Results represent the sum of free and bound forms in the sample. Solid and liquid fats and oils are covered; animal fats and used frying oils can be analysed after matrix validation. Milk and milk products are excluded.

Key technical topics and requirements

• Analytical principle: slow alkaline‑catalysed alcoholysis (transesterification) to cleave esterified MCPDs and glycidyl esters.
• Glycidol transformation: released glycidol is converted into monobromopropanediol (MBPD) to stabilise it for analysis.
• Derivatisation: MCPDs and MBPD are converted to PBA derivatives for GC/MS detection.
• Sample workflow: two aliquots (A and B) are prepared with surrogate and/or isotope‑labelled internal standards to:
  • quantify 2‑MCPD and 3‑MCPD,
  • obtain a preliminary glycidol result and correct for artifactual formation (induced glycidol).
• Quality controls: the method includes internal standards and checks to monitor ester‑cleavage efficiency and method performance.
• Scope limits: applicable to refined and unrefined vegetable oils and fats; animal fats and used frying oils require prior validation; excludes milk fats.

Practical applications and users

This ISO method is used where accurate quantification of MCPDs and glycidol is required for food safety, compliance and quality control:

• Food safety and public health laboratories monitoring process contaminants in edible oils and fats
• Commercial food testing and contract labs performing compliance testing for regulatory limits
• Oil processors and refiners conducting internal quality assurance and process optimisation
• Regulatory agencies establishing surveillance programs and enforcement actions
• Analytical chemistry researchers developing comparative methods or validation studies

Related standards

• ISO 18363-1 - fast alkaline transesterification (differential method; related approach for 3‑MCPD/glycidol)
• ISO 18363-3 - acidic method with conversion of glycidyl esters to MBPD esters (alternative procedure)
• Annexes in ISO 18363-2 provide chromatogram examples and interlaboratory validation data to support method implementation.

Keywords: ISO 18363-2:2018, MCPD, glycidol, 2‑MCPD, 3‑MCPD, GC/MS, phenylboronic acid, transesterification, fats and oils, analytical method.