Abstract:
Determination of free glycerol and mono-, di-, triglycerides contents
in biodiesel is the most critical parameter for the successful of transesterification
reaction. Gas Chromatography (GC) is one apparatus to get the composition
detail of glycerol and its derivative that formed after the tranesterification
reaction. Highly boiling point of that compounds cause problem in GC analysis.
Method of EN14105 offer the solution for this problem, since in this method the
compounds is transformed into more volatile and stable silyl derivatives in the
presence of pyridine and MSTFA (N-methyl-N-trimethysilyltrifluoroacetamide). To prevent the decomposition of compounds, the EN14105
suggests to providing GC with the OCI (On Column Injector Programmed
Temperature Vaporization) Unit. This method also use the internal standard for
determination of the sample concentration. High cost of the OCI unit and the
Internal Standard solution are the reasons why the modification of this method is
should be done. Method modification was done by replaced the OCI with
standard injector, followed by trial of external standard calculation method, and
arrange program temperature of column. Identification of compounds was done
by comparing retention time of standard materials to reference chromatogram
provide by the EN14105. Unfortunately , the analysis of experiment results
produce bad repeatability due to the unstable of detector responds. Experimental
result indicated that the modicication method of EN 14105 is appropriote only
for free glyserol content determination
