Chromatography

Key principles of chromatography

Components have different affinity to mobile phase and stationary phase

Stationary phase-solid/liquid held on solid support

Mobile phase-Liquid/Gas

Components separated based on:

Solubility in solvent

Retention in stationary phase

Polar molecules attracted to polar molecules

Non polar molecules attracted to non polar molecules

Explain how each of the 3 different chromatography work

Thin Layer Chromatography

Components are separated and to identify sample

Plate coated with silica: stationary phase

Liquid solvent: Mobile phase

The position of spot on paper depends on the affinity to mobile phase and affinity to stationary phase

Column chromatography

Silica gel beads: stationary phase

Liquid solvent : mobile phase

When sample moves down the column, components move at different rates, separating components on affinity to mobile phase and stationary phase

Retention time impacted by : temp, flow rate, length of column

Gas chromatography

Solid coated with oil: stationary phase

Unreactive gas, e.g N2: mobile phase

Retention time impacted by : temp, flow rate, length of column

Chromatography process

1)Wear gloves Mark starting line using pencil , 1cm from the bottom of plate and draw marks equal distance form one another

2)Using capillary tube to add small amounts of different sample to each spot, allow the plate to dry

3)add solvent in a developing chamber but ensure below starting line and add lid

4)Place plate developing chamber in fume cupboard and replace the lid

5)allow solvent to rise but stop and remove lid before solvent reaches top and using pencil, draw solvent front and allow to dry

6)Spray ninhydrin and heat/ place under UV light

7)Mark spots with pencil

8)Calculate Rf

Nylon, kevlar and terylene monomers