Gas Chromatography - Tandem Techniques - Examples of GC/MS Spectrometry Applications > Analysis of Waxes and Lipid Type Materials > Page 75
Figure 60. The Separation of a Series of Fatty Acids Using Total Ion Monitoring (after ref.20)
The technique was used to determine the fatty acid profiles of different cancer cell grown in the same media. An example of the separation of 15 different fatty acids using total ion current monitoring is shown in figure 60.
Evershed et al. (22) developed a method for extracting and analyzing lipid type material from archaeological specimens using GC/MS techniques. Chemical analysis is now a common procedure that is used to investigate archaeological remains.Ceramics can be particularly interesting as they can absorb various substances into the pores of the material and preserve them in an unchanged form for very long periods of time. Hence the lipid content of pottery can be a direct indication of the pots original contents and for what purpose it was used. As the pores are blocked with the very material that is being absorbed, little contamination from soil components takes place. The technique was developed using some freshly excavated ceramic potsherds, taken from the Raunds Area site in the Nene Valley Northhamptonshire UK.
Samples, about 2 g in weight, were scraped free from soil and ground to a fine powder in a carefully degreased pestle and mortar. A know mass of n-heptadecane was added as a standard, and the powder extracted twice with 10 ml of a mixture of chloroform and methanol (2+1) with supersonic agitation. After each extraction the mixture was centrifuged to remove the suspended solid. The extract was concentrated in a rotary evaporator and finally dried in a gentle stream of nitrogen. Trimethylester and ether derivatives were prepared by heating aliquots with excess N,O-bis(trimethylsilyl)trifluoroacetamide.