Analysis of Hydrocarbon in Common Fuels by Spme

OBJECTIVE

To introduces a derivatization produces routinely used for fat analysis in which nonvolatile fatty acids are chemically converted to the corresponding volatile methyl ester (FAME)

INTRODUCTION

Fatty acids are aliphatic monocarboxylic acids derived from or contained in esterified form in an animal or vegetables fat, oil or wax. Natural fatty acids commonly have a chain of 4 to 28 carbons (usually unbranched and even numbered), which may be saturated or unsaturated. By extension, the term is sometimes used to embrace all acyclic aliphatic carboxylic acids. This analysis is generally performed by gas chromatography following the conversion of the Fatty Acids into their corresponding Methyl Esters (FAME). Fatty acids are not sufficiently volatile for GC analysis. Gas chromatography is a technique for carrying out the separation and measurement of mixtures of materials that can be volatilized. These materials may be gases, liquids, or solids that have appreciable vapor pressures at temperatures up to a few hundred degrees. In capillary gas chromatography a stationary phase, generally a stable non-volatile liquid is spread in a thin film on a wall of column. A carrier gas acts as an inert moving phase to transport the sample components from an injection port at the head of the column through the column to a detector. Sample injection is an arrangement by which a solid, liquid, or gaseous sample is transmitted as a short pulse into the carrier-gas stream before it enters the column. The sample should be vaporized and carried to the leading end of the column in negligible time. The detector, commonly flame ionization, monitors the composition of the carrier-gas stream as it leaves the column. Simple, sensitive, and stable, the flame ionization detector has contributed in a major way to the explosive growth of gas chromatography. Esterification is the most popular method of derivatization technique. Esterification involves the condensation of the...