BS EN 14105 Fat and oil derivatives - Fatty Acid Methyl Esters (FAME) - Determination of free and total glycerol and mono-, di-, triglyceride contents
1 Scope
The purpose of this European Standard is to determine the free glycerol and residual mono-, di- and triglyceride contents in fatty acid methyl esters (FAME) intended for addition to mineral oils. The total glycerol content is then calculated from the obtained results.
Under the conditions described, the quantification limits are 0.001 % (m/m) for free glycerol, 0.10 % (m/m) for all glycerides (mono-, di- and tri-). This method is suitable for FAME prepared from rapeseed, sunflower, soybean, palm, animal oils and fats and mixture of them. It is not suitable for FAME produced from or containing coconut and palm kernel oils derivatives because of overlapping of different glyceride peaks.
NOTE For the purposes of this European Standard, the term "% (m/m)" is used to represent respectively the mass fraction.
WARNING - The use of this method may involve hazardous equipment, materials and operations. This method does not purport to address to all of the safety problems associated with its use, but it is the responsibility of the user to search and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2 Principle
Transformation of the glycerol and of the mono- and diglycerides into more volatile and stable silyl derivatives in presence of pyridine and of N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA).
Analysis of the sample after silylation, by gas chromatography on a short capillary column with thin film thickness, with an on-column injector or equivalent device, and flame ionization detection.
After a calibration procedure, the quantification of glycerol is carried out in presence of the internal standard 1,2,4-butanetriol.
Mono-, di- and triglycerides are directly evaluated in presence of an internal standard for each glyceride category:
glyceryl monononadecanoate (Mono C19) for monoglycerides;
glyceryl dinonadecanoate (Di C38) for diglycerides;
glyceryl trinonadecanoate (Tri C57) for triglycerides.
