Lipids: Lipid and Positive Result

2792 Words Aug 9th, 2013 12 Pages
Characterization of Saponifiable Lipids and Characterization & Isolation of Complex Lipids
Jan Kevin Roxas, Nashiba Samad, Erickson Santos
Department of Chemistry, University of Santo Tomas, Manila, Philippines

Abstract Lipids building blocks of different organic material that are water insoluble. This can be divided into simple and complex lipids that have several forms like waxes, triacylglycerols, phosphoacylgylcerols, sphingolipids, eicosanoids, isoprenoids and many other. To identify, isolate and characterize some or all components of a given lipid sample several test can be performed like Grease-spot test, Acrolein test, Saponification test, Unsaturation test, Iodione test, Liebermann-Buchard test, Salkowski test, Phosphate
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Discard the aqueous layer.
9. Return the organic layer to the separatory funnel.
10. Repeat steps 7 and 8
11. Dry the organic layer over anhydrous Na2SO4.
12. Filter off the solution into a clean Erlenmeyer flask.
13. Add a pinch of hyroquinone and transfer to an evaporating dish.
14. Evaporate to dryness over a beaker of warm water in the hood.
15. Obtain a sticky residue.

Results And Discussion Different test for saponification can be done to identify if a given lipid contains ester or not. Some of this test can also be used to test for unsaturation degree of an oil sample. Some of this characterization tests are grease-spot test, saponification test, acrolein test, and unsaturation test. Below are the working principle of the tests listed before.

* Grease-spot Test – the working principle of this test is that most grease or fat have high boiling point meaning they are non-volatile. In room temperature, the spot of water can absorb enough heat from the air and then evaporize. But the spot of grease can never absorb enough heat to evaporize. When the liquid is inside the sheet of paper, it diffracts light. So, light can pass from one side of the paper to another side. This gives the phenomenon of "translucent". When there is no liquid in the paper, there is no diffraction. So, light cannot pass it through.3 The positive result for this test is a translucent spot.

* Saponification Test - a process usually hydrolyzation in which triglycerides