Fatty acid esters of 3- and 2-monochloropropanediol (3-MCPD-e, 2-MCPD-e) and glycidol (Gly-e) are process contaminants that are formed, for example, during the refining of edible oils and fats. After ester cleavage during digestion in the human body, they pose a relevant health risk and must therefore be determined in edible oils and fats and in fatty foods.
For the indirect analysis of 3-MCPDe and Gly-e, several standardized analytical methods are currently available, which are defined in various standard method documents. GERSTEL previously developed and presented a comprehensively automated analysis system following ISO 18363-1, AOCS Cd 29c-13, DGF C-VI 18 (10) (GERSTEL AppNote 191). In this document, we present a system for comprehensive automation of the ISO 18363-4 (Zwagerman/Overman) method, the most recent standard method available for 3-MCPD-e, 2-MCPD-e and Gly-e determination.
When performing sample preparation and sample introduction with the GERSTEL MultiPurpose Sampler (MPS), fitted with the required modules and options, the only manual steps the user needs to perform are weighing an aliquot of oil into a sample vial, capping it, and placing it in the MPS sample tray. All other sample preparation steps listed in the standard method and the subsequent GC-MS/MS determination are performed automatically. Limits of quantification (LOQs) of 19 μg/kg for 3-MCPD, 17 μg/kg for glycidol and 16 μg/kg for 2-MCPD are achieved, which is well below the LOQs of 100 μg/kg required in the ISO standard for all three compounds. The precision (repeatability) is below 6% relative standard deviation for all three compounds. The accuracy was verified by analyzing a sample from a proficiency test and a sample for which external analysis results were available. The system and method proved to be robust and reliable when processing real samples. The complete setup and method parameters are bundled and made available for end-users to enable rapid method setup and analysis of 3-MCPD, 2-MCPD and glycidol according to ISO 18363-4.