Determination of Quantity of Methyl Ester in Biodiesel by Thin Layer Chromatography (TLC)

Abstract

According to the notification of Department of Energy Business biodiesel in Thailand can be categorized into two types, which are biodiesel for agricultural engines (commodity biodiesel) and fatty acid methyl ester (FAME)-typed biodiesel (biodiesel B100). These two types of biodiesel have different characteristics and specifications. As reported in the literature, the minimum methyl ester content in B100 is specified at 96.5 percent by mass. In this study, the utilization of ultraviolet (UV) light operation at 254 nm wavelength coupled with Thin Layer Chromatography (TLC) is proposed in order to determine methyl ester content in unknown biodiesel. The silica gel on the TLC plate is first impregnated with a fluorescent material that glows under UV light. A spot then can interfere with the fluorescence and appear as a dark spot on a glowing background. A comparison between the spot of unknown biodiesel and spot of B100 can be made where methyl ester content in B100 is exactly known. It is found that the result of methyl ester content in unknown sample obtained from using UV light is consistent with that obtained from sophisticated instrument in chemical laboratory. Thus, this simple and affordable technique can be utilizated in the preliminary determination of type of biodiesel.