Chromotography Practica Flashcards
1
Q
Why is chromatography used?
A
-To identify which amino acids are present in a mixture of amino acids
2
Q
What 3 steps prepare for chromatography?
A
- Paper is cut to fit the tank in vertical position.
- Horizontal line drawn in pencil a few cm above base
- Solution spotted on pencil line by micro pipette, adding a drop once dried
3
Q
Why should the paper be held in vertical position?
A
- So it’s long enough to allow attachment to lid and drop to just above the base of tank. long enough to extend into solvent
- solvent is placed at bottom
4
Q
In what position should the line drawn lie?
A
Above the solvent when chromatography is placed in solvent
5
Q
Why should you add more drops of the solution when’s it dried?
A
- As it allows the solution to be more concentrated
6
Q
What 3 precautions must be taken before running the chromatogram?
A
- Concentrated spot forms as small an area as possible
- Avoid Contamination - hold at edges and avoid setting on benches
- Before placing paper in tank the solvent should be added and lid placed on top to allow the atmosphere to become saturated
7
Q
What 4 precautions must be taken during the running of the chromatogram?
A
- The line and spots don’t make contact with solvent
- Chromatogram is securely attached
- Not suspended at an angle
- Run of solvent must be stopped before it reaches the top
8
Q
What does the solvent carry as it runs up the chromatogram?
A
Amino acids
9
Q
How do you develop the chromatogram?
A
- must be dried before solvent dries
- mark the solvent front
- Sprayed with ninhydrin in a fume cupboard
10
Q
What should the chromatogram be re dried with?
A
- Hair dryer or oven
11
Q
What is the Rf value?
A
Distance moved by solute divided by distance moved by solvent front
