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Now you will focus on the methods to determine the fatty acid profile of a food (in this case margarine). At the end of this part you will finalize your database.

Columns

For GLC several columns can/have been be used: packed columns and capillary columns. Many data, especially older data

-before 1990- on fatty acid contents in FCDB are based on fatty acid separations using packed columns. Modern gas chromatography uses capillary columns. Packed columns are glass columns with a length of about 2 m and with an internal diameter of 2-4 mm. The liquid stationary phase is coated on support material: diatomaceous earth of uniform size. Capillary columns are often 25-50 m long and made of fused silica. The internal diameter is about 0.25 mm. The liquid stationary phase is coated on the inner wall of the tube: wall coated open tubular columns (WCOT). The thickness of the liquid phase is about 0.2-0.4 µm. In general capillary columns give a much better separation -also called higher resolution- than packed columns.