Learning Aim C
Chromatography:
Chromatography is a method used to separate mixtures of colored
components. There are two stages to chromatography (Mobile Phase and Stationary
Phase). The mobile phase is the solvent that travels through the paper carrying various
chemicals with it. The stationary phase does not move and remains motionless on the
paper. The mixture is first dissolved in a liquid known as the mobile phase, and then
passed through a solid known as the stationary phase. Different components of the
mixtures travel at different rates which causes them to separate from each other.
Chromatography is used for creating vaccinations, food testing, beverage testing, drug
testing and forensic testing etc. There are 2 types of chromatography (Paper
chromatography and Thin layer Chromatography(TLC)).
1:Paper Chromatography:
Paper chromatography is used to determine if a substance is
pure or impure and is also used to separate soluble substance mixtures to see which
chemicals are present. It can be used to analyse both coloured and colourless substances.
For colourless substances a locating agent is used to form coloured products.
2:Thin Layer Chromatography(TLC):
Thin Layer Chromatography is carried out to separate
components using a thin uniform layer of silica gel or alumina coated onto a piece of
glass, metal or rigid plastic. It can be used to monitor the course of a reaction on an
analytical scale or to purify small amounts of a compound on a preparative scale.
Thin Layer Chromatography of plant pigments
Equipment: