Application note: 3-MCPD/Glycidol: The A-Method automated, AOCS Cd 29a-13

Automated GC/MS analysis of oil for 3-MCPD and Glycidol using AOCS Cd 29a-13 with ultra-sonication plus evaporation for best sensitivity, stability.

This AppNote describes a solution for fully automated determination of 3-MCPD and Glycidol in edible oils including sample preparation. The solution is based on the methods ISO 18363-3 and AOCS Cd 29a-13, often referred to as the “A-Method”. These methods enable the analyst to determine glycidol, 3-MCPD and 2-MCPD in a single GC/MS run. In the first step, Glycidyl esters (GEs) react with acidified sodium bromide to form 3-MBPD-ester.

3-MCPD-, 3-MBPD- and 2-MCPD- esters are then saponified to their free forms in acidic methanol solution and subsequently derivatized with phenylboronic acid (PBA) enabling quantitative determination of all three in one GC/MS run.  The sonication bath makes derivatization at room temperature possible. The work presented here involves automated evaporation steps as prescribed in the abovementioned official methods. The required limits of detection are reached using a single quadropole mass spectrometer (MSD). A further important aspect of the evaporation step is that it removes excess derivatization reagent, which could otherwise build up in the GC/MS system and influence system stability.

It is demonstrated that method ISO 18363-3, which is equal to method AOCS Cd 29a-13 can be automated using the GERSTEL MPS. The obtained results show good correlation with reference data. The excellent standard deviations achieved for the complete sample preparation and analysis workflow speak in favor of automation.