Chromatography (Amino acid & Photosynthetic pigments)

Question 1

Describe how to carry out a thin layer chromatography

Answer 1

• Wearing gloves draw a pencil line on the chromatography paper 2 cm from the bottom edge, handle the plate at the very edges
• Place four equally spaced spots on the line
• Get your first mixture and place a drop of the solution onto one of the dots, then once the first drop has dried add another drop using a pipettes
• Do the same for the other solutions
• Place the plate into a jar containing the solvent and close the lid - ensure the solvent is no more than 1cm deep
• Leave the plate until the solvent reaches about 2 cm from the top. Remove the plate, draw a pencil line on the solvent front and allow it to dry
• Spray the plate with ninhydrin spray in a fume cupboard which should create purple/brown colour for all amino acids present. Mark the centre of each spot with a pencil
• Calculate the Rf rate and note this down at the very least

Question 2

How do you calculate the Rf value

Answer 2

Distance travelled by component
Rf = ————————————————-
Distance travelled by solvent