{"id":43864,"date":"2020-10-27T14:30:00","date_gmt":"2020-10-27T14:30:00","guid":{"rendered":"https:\/\/discover.restek.com\/uncategorized\/analysis-of-fames-in-biodiesel-fuel-pro-ezgc-modeling-software-ensures-proper-column-selection\/"},"modified":"2026-01-28T15:49:44","modified_gmt":"2026-01-28T15:49:44","slug":"analysis-of-fames-in-biodiesel-fuel-pro-ezgc-modeling-software-ensures-proper-column-selection","status":"publish","type":"post","link":"https:\/\/discover.restek.com\/zh-hans\/application-notes-zh\/pcan2889\/analysis-of-fames-in-biodiesel-fuel-pro-ezgc-modeling-software-ensures-proper-column-selection","title":{"rendered":"Analysis of FAMEs in Biodiesel Fuel: Pro EZ<\/em>GC Modeling Software Ensures Proper Column Selection"},"content":{"rendered":"\n

Abstract<\/h2>\n\n\n\n

Polar columns were evaluated for the analysis of fatty acids methyl esters (FAMEs) in finished B100 biodiesel according to method EN 14103 (2011). Using Restek\u2019s Pro EZ<\/em>GC chromatogram modeler, a high cyano phase Rt-2330 column and a polyethylene glycol phase FAMEWAX column were compared. The modeling software predicted an unacceptable coelution between the internal standard (C19:0 FAME) and FAME C18:2 when using the Rt-2330 column. However, the modeler also predicted that the FAMEWAX column would separate all the compounds of interest, which was demonstrated empirically. In addition, the results on the FAMEWAX column showed excellent repeatability for both total FAMEs and the linolenic acid methyl ester component.<\/p>\n\n\n\n

Introduction<\/h2>\n\n\n\n

Biodiesel is a diesel fuel made from plant or animal fat feedstocks. These biologically sourced fats, predominantly triglycerides (1), are converted into fatty acid methyl esters (FAMEs) via a transesterification reaction that occurs in the presence of methanol and a basic or acidic catalyst. This reaction produces biodiesel fuel and also generates glycerol as a byproduct. The biodiesel FAME profile is determined by the type of fat that is used in the reaction and, therefore, the specific composition of biodiesel can vary from saturated to unsaturated FAMEs. The ester composition of biodiesel is used to determine product quality and to calculate its cetane number. According to the method EN 14214, which regulates biodiesel quality, ester content in 100% biodiesel (B100 product) has to be greater than 90% total fatty acid methyl esters by mass. In addition, the linolenic acid methyl ester (methyl linolenate) content must be between 1% and 15% by mass (2).<\/p>\n\n\n\n

European standard method EN 14103 (2011) is widely used for the analysis of FAMEs in biodiesel. It is specifically used to determine both the FAME composition and, simultaneously, the linolenic acid methyl ester concentration. Linolenic acid methyl ester is a methyl ester of a polyunsaturated fatty acid where both trans<\/em> and cis<\/em> isomers can be present. A high concentration of linolenic acid methyl ester is undesirable because its poor oxidation stability can change fuel properties and form undesirable species (3).<\/p>\n\n\n\n

According to method EN 14103 (2011), polar FAMEs in biodiesel can be resolved and quantitated using gas chromatography and highly polar capillary column (2). Polar columns, such as high cyano (Rt-2330) or polyethylene glycol columns (FAMEWAX) offer excellent retention and selectivity for polar FAME compounds. This application note uses the Pro EZ<\/em>GC chromatogram modeling software<\/a> to assess the performance of two polar analytical columns for EN 14103 (2011) biodiesel analysis and then compares the model output to empirical data.<\/p>\n\n\n\n

Experimental<\/h2>\n\n\n\n

Rt-2330 and FAMEWAX columns were selected for this experiment because they are highly polar phases that have been shown to generally perform well for FAMEs analysis. Both columns were initially evaluated using two criteria: selectivity using Pro EZ<\/em>GC chromatogram modeling software and overall method suitability. The Pro EZ<\/em>GC modeler conditions were customized to match EN 14103 (2011) operating conditions and the most prevalent FAMEs were chosen and modeled along with C19:0 as an internal standard.<\/p>\n\n\n\n

The results from the most promising modeled chromatogram were confirmed in the laboratory by analyzing a Restek food industry FAME standard (30 mg\/mL in methylene chloride,\u00a0cat.# 35077) and a single compound FAME C19:0 internal standard (10 mg\/mL in toluene,\u00a0cat.# 35055) on a FAMEWAX 30 m x 0.25 mm x 0.25 \u00b5m column (cat.# 12497). Commercially obtained canola and soy biodiesel B100 samples were also analyzed following method EN 14103 (2011).<\/p>\n\n\n\n

In order to assess repeatability, total ester content and linolenic acid methyl ester content over multiple analyses were calculated as described in the method.<\/p>\n\n\n\n

Results and Discussion<\/h2>\n\n\n\n

The modeled Pro EZ<\/em>GC chromatogram for the Rt-2330 column (Figure 1) clearly illustrates a coelution between the internal standard FAME C19:0 and trans<\/em> C18:2 FAME, which can be present in biodiesel. This means that the Rt-2330 column is not suitable for the analysis of FAMEs in biodiesel under the method conditions because the internal standard was not completely resolved. Predicting this problem using the Pro EZ<\/em>GC chromatogram modeler took only minutes on the computer, providing a substantial savings of time and money compared to determining this experimentally in the lab.<\/p>\n\n\n

Figure 1:<\/strong>\u00a0Pro\u00a0EZ<\/em>GC modeling software predicts the coelution of internal standard FAME C19:0 with\u00a0trans<\/em>\u00a0C18:2 FAME on an Rt-2330 column. This allows analysts to remove the column from consideration without the time and expense of testing its performance in the lab.<\/div>
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