isolation of cholesterol

Isolation of cholesterol

Cholesterol is the most common steroida. Cholesterol is rarely found in plants, although it is closely associated with plant sterols such as stigmasterol, is an important component in the plant.

This experiment uses samples egg yolk. Isolation of cholesterol begins with the addition of a solution of ethanol and ether in the ratio 2: 1. Ethanol tends to be polar and non-polar ether which tends to be a combination of solvent can dissolve the phospholipids that are ampifatik cholesterol and triglycerides in the egg yolk. Then perform the filtration to separate the fat dissolved in ether and ethanol with other components such as pigments (lutein and astaxantin) and proteins. The resulting filtrate is colorless (transparent) and a yellow precipitate. This is consistent with the theory Gunawan (2009), as described in the literature.
Precipitate and then rinsed with hexane to dissolve the lipid component extracted has not participated in the early stages. Hexane is an excellent solvent for the extraction of neutral lipid components. Furthermore, the results of the extract is poured into a separatory funnel and allowed to stand for ± 30 minutes to separate the components are soluble in fats (triglycerides hexane) with liposoluble components of ethanol-ether (cholesterol and phospholipids). Hexane solvent will be at the top of the funnel, while the ethanol-ether will be on the bottom of the funnel. This is due to a lower density ethanol hexane-ether. (Palacios and Wang, 2005)
The next step is the heating. Heating aims to evaporate the organic solvent, so that leaves only the fat component. This may be because the boiling point of the solvent less than the boiling point of the fat. Further cold acetone added components of heating that dissolve the fat, which is alcohol. White precipitate formed which is a phospholipid / lecithin. This is consistent with the theory Szuhaj (1989) described in the literature.

Test conducted on Salkowski final filtrate produces red ring between the two layers. These results suggest that the positive yolk contains cholesterol.

The presence of cholesterol can be determined by using some color reaction. One of them is the Salkowski reaction. If cholesterol dissolved in chloroform and the solution was poured

The presence of cholesterol can be determined by using some color reaction. One of them is the Salkowski reaction. If cholesterol dissolved in chloroform and the solution was poured over a solution of concentrated sulfuric acid carefully, then the acid yellow to green when the subject flouresensi light. Part chloroform is blue and turn red and purple. Solution of cholesterol in chloroform when added acetic acid anhydride and sulfuric acid, then the solution will initially be red, then blue, and green. This is called the Lieberman Burchard reaction. The green color is happening is apparently proportional to the concentration of cholesterol. Therefore reaction Burcharddapat Lieberman used to quantitatively determine cholesterol

over a solution of concentrated sulfuric acid carefully, then the acid yellow to green when the subject flouresensi light. Part chloroform is blue and turn red and purple. Solution of cholesterol in chloroform when added acetic acid anhydride and sulfuric acid, then the solution will initially be red, then blue, and green. This is called the Lieberman Burchard reaction. The green color is happening is apparently proportional to the concentration of cholesterol. Therefore reaction Burcharddapat Lieberman used to quantitatively determine cholesterol