Keywords: Free Fatty Methyl Esters (FAMES), Automation
Every laboratory is under pressure to quickly and consistently deliver accurate results and to provide clear answers faster than ever before while reducing the cost per analysis. Analysis systems that meet these criteria are always welcome. Application scientists from Bespak Europe Ltd. and from Anatune Ltd., both based in the U.K., have provided such a solution for automated derivatization and GC/MS determination of fatty acids. The approach taken to the challenge: Automated sample preparation combined with discrimination free introduction of the derivatized analytes to the GC/MS system. Automated sample preparation in this case includes adding an internal standard and derivatizing the fatty acids.
Keywords: Automation, Total Fat, Trans Fat, Saturated Fat, Food, Gas Chromatography, Microwave, Saponification, FAMEs
Determination of total fat, saturated fat, monounsaturated fat and trans fat content in food samples is necessary for complying with applicable food labeling requirements. A typical procedure for saponification of the sample involves refluxing with sodium methoxide in methanol, followed by a second reflux with boron trifluoride in order to esterify the free fatty acids. Prior to injection into the gas chromatograph, the fatty acid methyl esters (FAMEs) must be extracted from the reaction mix and the extract must be dried. The reflux times are typically an hour. After the sample is prepared, the round bottomed flask and condenser must be cleaned. This process is laborious and time consuming, which limits sample throughput. A combined autosampler and liquid handling robot, which is commonly used for a wide variety of sample preparation techniques can be interfaced directly to a CEM Discover SP-D microwave unit. In this way, a single integrated system under GERSTEL MAESTRO software control can perform saponification of fats in combination with further sample preparation steps and finally introduction to a GC or HPLC system.