TLC stands for thin layer chromatography. This technique is used to identify the compounds you have based on their polarity. TLC has a stationary phase and a mobile phase. The stationary phase consists of a thin sheet of plastic, glass or aluminum coated in a substance such as silica gel. The mobile phase consists of the solvent, into which TLC is immersed. Most of the time TLC place is coated in polar substance such as silica and therefore the solvent is non polar, such as hexane.
In the beginning of the procedure, the student puts a drop each of the control substances as well as experimental outcome. He/she then immerses the sample into the fluent, which over time, moves up the plate. The final location of each spot depends on the polarity of the substance. Since silica is polar, molecules that are more polar will stay at the bottom not moving as much, while molecules that are non polar will move more with the eluent and end up higher on the plate. The distance travelled by the substance can be measured and divided by the total distance travelled by the eluent, giving us Rf value (retardation factor).
We can also compare the Rf values of the unknown substances to the known control substances to compare them, and determine whether the experiment was successful or not.
Think layer chromatography has a variety of uses. It is used to check on the progress of reaction as well as identify the purity of the product and identity the compounds present in a given mixture. It is a technique used often by students taking the organic chemistry lab.
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