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Thursday, April 1, 2010

CHROMATOGRAPHY

Chromatography is one of the main techniques to separate the mixture into its components with the help of differences in physical properties of each component or mixture of compounds into the separation of pure compounds and to know the quantity Chromatography is commonly used to test for example, and compounds flavonoida isoflavonoida contained in tofu, tempeh, soy powder and Tauco and Scoparia dulcis, Lindernia anagalis, and Torenia Violacea. This experiment will study about thin layer chromatography.



Thin Layer Chromatography (TLC) is a way of separating mixtures of compounds into pure compounds and knowing the quantity In addition, the TLC can be used to separate compounds - which are hydrophobic compounds such as lipids - lipid and hydrocarbons are difficult to do with paper chromatography. TLC can also be useful to find the eluent for column chromatography, analysis of fractions obtained from column chromatography, chromatographic identification of compounds, and small-scale isolation of pure compounds. Solvents selected for the developer adjusted with solubility properties of compounds analyzed.

The working principle is based on the stationary phase TLC (silica gel) and motion dase (methanol, petroleum ether). Pelaksaanan thin layer chromatography using a thin layer of silica or alumina is uniform on a glass plate or a metal or hard plastic. Stationary phase for thin layer chromatography are often also contain a substance which can berpendarflour in ultraviolet light. Mobile phase is a solvent or solvent mixture as appropriate. Implementation is usually in the color separation is a combination of several dyes or separation and isolation of plant pigments green and yellow. Data obtained from the TLC is the value of Rf. Rf value can be defined as the distance traveled by the compound from the origin divided by the distance traveled by the solvent from the origin. Therefore the number Rf is always smaller than 1.0. The value of Rf is useful for identification of compounds. Rf value for pure compounds can be compared with the Rf values of standard compounds.

Factors affecting the movement of spots on TLC diataranya experimental techniques, the nature of the absorber and the degree of its activities, the chemical structure of compounds which were separated, and the flatness of the thick layer of absorbent, solvent (and the degree of purity) mobile phase, the number tetsan used, the degree saturation and steam in a vessel development in use, temperature, and equilibrium. Separation of these compounds by TLC using a principle like disolved like, that is a principle in which the solubility of a substance will dissolve only in the appropriate solvent. In other words, a substance that has the properties of polar substances will dissolve in solvents which are also polar and non polar substances will dissolve in non polar solvents. This principle is called the principle of like dissolve like. Stages of analysis by thin layer chromatography same as in paper chromatography. Excess laspis chromatography thin compared with paper chromatography elution time is relatively shorter and can be used for quantitative analysis. Detection of spots on thin layer chromatography tekadang easier than paper chromatography because the stain does not color or do not fluoresce when subjected to UV (ultraviolet) and can be shown by way of board developer iodine vapor will react with the component.
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