Chromatography is a laboratory technique that is used to separate a mixture. It is used because
different components of the mixture travel through the stationary phase at different speed
causing them to separate from one another.
How does It work?
Chromatography works by moving the dissolved substance, liquid or gas via a filtration system,
chromatography operates. When the molecules move through the filter, the molecules detach
into layers. The separation mechanism depends upon the extent of filtering, which is
determined by the kinds of molecules that are to be separated.
We are going to discuss the following chromatography, paper chromatography, thin layer
chromatography for plant pigmentation (TLC) and amino acids.
Paper chromatography.
TLC separates mixtures of components to allow identification of the mixture. In thin layer
chromatography there is a stationary phase and a mobile phase. In stationary phase the
substance is not moving so the mobile phase is the moving phase which flows with the
stationary phase and carries the compound while pushing it up. TLC is simple to work with and
it is inexpensive. The distance and speed traveled by a solvent along the chromatogram relies
as to how closely bound the substance is to the stationary phase. The polarization of the
substance also defines how far TLC plate can go. Once the front of the solvent is about a
centimeter from the top of the plate, the Rf must be labelled. (Wikipedia, 2020)
Materials.
Test tube as a developing chamber.
TLC plate.
Pencil.
Water as a solvent.
Ruler.
green marker as a water soluble.
When the solvent has moved the compound about 1 cm to the top of the silica plate it Is
marked and the Rf values can be calculated.
Method.
1. Cut the silica plate into the proper size of the developing chamber. Make sure it is
handled by its edges or handle it with a capillary tube because we don’t want to
contaminate it.