Chromatography is the method of separating chemical substances that makes uses of the relative rates at which they are adsorbed from a moving stream of gas or liquid on a stationary substance, which is usually a finely divided solid, a sheet of filter material, or a thin film of a liquid on the surface of a solid. It is a versatile method that can separate very complex mixtures even in the absence of detailed previous knowledge of the number, nature, or relative amounts of the individual substances present.
Chromatography has many uses in which chemists find exciting. One of the uses that chromatography has is to measure or identify low concentration of substances. Another use is to separate and identify products to chemical reaction. Chemists also use this method to separate pure substances from impurities.
There are three main methods of common chromatography: liquid column, thin layer, and gas chromatography. The method that was used in the lab was thin layer chromatography. Thin layer chromatography uses a plate, which is a thin, flat sheet of glass or other material that is coated with an adsorbed film. Chemists place a drop of the mixture on one end of the plate, then stand that end of the plate in a shallow pool of liquid. The liquid travels up the film, moving along with it. The substances separate from one another as they are adsorbed.
The Essay on Column and thin layer chromatography 2
... thin layer chromatography, paper or high performance liquid chromatography for liquid – liquid separation and vapor-phase chromatography for gas – liquid chromatography. Column chromatography is used to separate ... mobile. The principle of chromatography is that substances differ in their partition ... the colored components in thin layer chromatography. MATERIALS AND METHODS MATERIALS The apparatus used ...
Procedure
First, a TLC plate must be marked with nine equally spaced marks for each over the counter medicine. Second, take the sample of the medication and crush it into a powdery substance. Third, mix 1-2mL of ethanol and the crushed medication into a pipette allowing the ethanol to filthy through. Fourth, place the long, slender capillary tube to get a drop of the mixture. Fifth, place the drop onto the TLC plate where it is labeled to go. After that, put everything back into a test tube rack and pass it clockwise. When you get the next medication, repeat the steps starting with getting a drop and putting it onto the TLC plate. When that is finished, place the plate into a cup with a little bit of fingernail remover and let stand for about five minutes. When the liquid gets about one centimeter from the top of the plate, remove it and use an UV lamp to see how the medication is reacting to the TLC plate. Then, take a pencil and dot where all of the spots have stopped. Measure the distance that the spots traveled and record the data onto the worksheets. When finished with that, return all materials to the proper place.
