Modification Method Of EN14105 For Determination Of Free Glycerol And Mono-Di-Triglycerides Contents In Biodiesel

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