SIMULTANEOUS DETERMINATION OF GLYCEROL, AND MONO-, DI- AND TRIGLYCERIDES IN BIODIESEL FROM TRA FISH FAT BY GAS CHROMATOGRAPHY

Abstract

Biodiesel is an alternative fuel produced from renewable resources like vegetable oils or animal fats, through transesterification reaction with methanol and sodium hydroxide as catalyst. In biodiesel, low levels of total glycerin ensure that high conversion of the oil or fat into its mono-alkyl esters has taken place. High levels of mono-,di-, and triglycerides can cause injector deposits and may adversely affect cold weather operation and filter plugging. Thus, in biodiesel, glycerin free content, monoglyceride (MG), diglyceride (DG) and triglycerides (TG) are important indicators of quality assessment of biodiesel, and also the criteria used to evaluate the metabolic rates of chemical reaction of methanol or ethanol in the preparation of biodiesel. In this study, gas chromatography method (GC/FID) was used for the simultaneous determination of glycerol, and mono-, di- and triglycerides in biodiesel from tra fish fat. According to EN14105, individual triglyceride (TG), diglyceride (DG), monoglyceride (MG) and free glycerin were separated in 35 – 40 min after treating with N– methyl–N–trimethylsilyltrifluoroacetamide (MSTFA) to give the corresponding trimethylsilyl (TMS) derivatives of the hydroxyl groups. The parameters for the column oven, injector, detector, and limit of detection (LOD), and limit of quantitation (LOQ), recovery performance, and conditions of sample processing methods are also examined. Survey results obtained analytic methods with detection limits and quantification limits glycerin respectively LOD = 0.033 (mg/kg), LOQ = 0.11 (mg/kg). Limits of detection and quantification limits for monoolein as LOD = 7.27 (mg/kg), LOQ = 24.22 (mg/kg), as LOD = 7.63 diolein (mg/kg), LOQ = 25.45 (mg/kg) and triolein LOD = 45 (mg/kg), LOQ = 150 (mg/kg). The recovery efficiency of method was greater than 90%.

Keywords: Biodiesel, glycerin, GC/FID, MSTFA, DB 5HT.