Gas Chromatography

TITLE

Fatty Acid detrmination using Gas Chromatography

OBJECTIVE

To analyse nonvolatile fatty acid that are chemically converted into volatile methyl esters (FAME) by using Gas Chromatography

ABSTRACT

Fatty acid is not volatile enough to be used for Gas Chromatography analysis. Besides, fatty acid are reactive compound and too polar to achieve good separation. If the acid is directly injected during into GC, the chromatogram obtained will show peak tailing due to the adsorption and non specific interaction with the GC column. Thus, derivatization process need to be conducted since this process will chemically modify the compound to produce a new compound so that it can easily ‘blend’ with the properties of GC column.

INTRODUCTION

Fatty Acid

In the normal human diet, about 25% to 50% of te caloric intake consist of fats and oils. These substances are the most concentrated form of food energy in our diet. When metabolized, fat produce about 9.5kcl of energy per gram. Fat and oil are ester of glycerol, called glycerides or acylglycerols. The most common fatty acid have 12,14,16 or 18 carbons, although acid with both lesser and greater number of carbons are found in several fats and oils. The fatty acid have both saturated and unsaturated. The saturated acid tend to be solids, while the unsaturated acids are usually liquids. The physical and chemical properties of a fat depends on the composition of the fatty acid mixture. Animal fats tend to have a larger proportion of long chain saturated acids and are solids at room temperature. Fats from plant sources contain a higher proportion of unsaturated acids and are often liquids at room temperature due to hydrogen bonding. Polyunsaturated fats are usually of vegetable origin. Crisco is an example of a vegetable-derived, unsaturated fatty acid that has been hydrogenated to form a solid material. Fats are used in cooking because they are very high boiling compounds. Their high boiling points therefore make this...