Abstract
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, when edible oils and fats are refined. After ester cleavage during digestion in the human body they pose a relevant health risk and therefore need to be determined in edible oils and fats and in fat containing food.
A series of standardized analysis methods for indirect analysis of 3-MCPDe and Gly-e are currently available, laid down in different standard method documents. GERSTEL previously developed and presented comprehensively automated analysis systems following ISO 18363-1, AOCS Cd 29c-13, DGF C-VI 18 (10) (GERSTEL AppNote 191) and ISO 18363-3, AOCS Cd 29a-13 (GERSTEL AppNote 217). 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 the analysis using the MultiPurpose Sampler (MPS) along with the necessary modules and options, the only manual steps the user needs to perform are weighing an aliquot of oil into a sample vial, sealing it, and placing it in the MPS sample tray. All other sample preparation steps listed in the norm and the subsequent GC-MS/MS determination are performed automatically. Limits of quantification (LOQs) of 15 μg/kg for 3-MCPD, 44 μg/kg for glycidol and 5.7 μg/kg for 2-MCPD are achieved, well below the 100 μg/kg LOQs required in the ISO standard for all three compounds. It was proven that by integrating an automated evaporation step into the workflow, even lower LOQs can be achieved. Precision of repeat analyses is mainly below 5% relative standard deviation for all three compounds, except for glycidol at low concentrations. Trueness was verified by analyzing a sample from a proficiency test and a sample for which external analysis results were available. When processing real world samples, the system and method were shown to work ruggedly and reliably. The complete setup and method parameters are bundled and made available for end-users enabling rapid method setup and analysis of 3-MCPD, 2-MCPD and glycidol by ISO 18363-4.
Keywords
3-MCPD, 2-MCPD, Glycidol, edible oil and fat, ISO 18363-4, Zwagerman/Overman method, laboratory automation
