12. Juni 2017
New AppNote: Determination of 3-MCPD and Glycidol in edible oils
Fully automated GC/MS determination of 3-MCPD and Glycidol based on standard methods including an evaporation step provides excellent sensitivity and system stability
Abstract:
3-MCPD and Glycidol and especially their fatty acid
esters are process contaminants that are formed, for
example, when edible oils and fats are refined. At
least some of the above-mentioned substances are
classified as potential human carcinogens, a fact which
has prompted the introduction of rules and regulations
that specify tolerable daily intake values and maximum
levels in edible oils. Different analytical methods are
available for the determination of these compounds.
These methods follow two different strategies:
Direct determination or, more commonly, indirect
determination of the contaminants.
This AppNote describes a solution for fully
automated determination of 3-MCPD and Glycidol in
edible oils based on the reliable indirect method DGF
C-VI 18 (10), similar to the ISO 18363-1 and AOCS
Cd 29c-13 methods that are essentially identical.
The edible oil sample is divided into two parts
(assays A and B). Both are saponified using a
Sodiumhydroxymethanol solution, but different
quenching methods are used. In assay A, free Glycidol
is converted to 3-MCPD using acidic quenching
conditions in the presence of chloride. In contrast, for
assay B, the quenching reagent is an acidic chloride
free salt solution, in which free Glycidol is not
converted into 3-MCPD. Following derivatization, the
3-MCPD amounts in both samples are determined by
GC/MS as Phenylboronic acid (PBA) esters. Assay
B is used to determine the amount of 3-MCPD in the
sample while assay A provides the combined amounts
of 3-MCPD and Glycidol. The amount of Glycidol is
determined as the difference between the assay A and
assay B results.
The work presented here involves an automated
evaporation step as prescribed in the abovementioned
official methods. This ensures that for most matrices,
the required limits of detection can be 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 18363-1,
which is equal to both method AOCS Cd 29c-13
and method DGF C-VI 18 (10), 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.
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AppNote 191 Fully Automated Determination of 3-MCPD and Glycidol in Edible Oils by GC/MS Based on the Commonly Used Methods ISO 18363-1, AOCS Cd 29c-13, and DGF C-VI 18 (10) |