A2 Practicals Flashcards
(7 cards)
State how after hydrolysis amino acids can be identified
By thin layer chromatography
What is the paper coated with in thin layer chromatography
Silicon dioxide(slica) and it’s a thin layer
What is the silica knwon as
The stationary phase
State the procedure in Tlc when using amino acids
A one cm line is drawn up a plate and small dot containing the amino acids to be separated is placed on the line the plate is then placed in the solvent in a tank ( with the starting line being above the initial level of the solvent)
A lid is placed on the tank which causes the inside of the tank to be saturated with solvent vapour which enables it to rise and by doing so it allows the amino acids to rise also
When the solvent has reached the top of the plant the plate is removed and the position of the solvent is marked , ninhydrin or uv light is used to visualise the position of amino acids on the plate
The rf value can then be calculated
By using distance moved by spot/distance moved by solvent
Then rf values are compared
Why is uv light or ninydrin used to visualise amino acids
As they are colourless
What determines how close the amino acid to the solvent in Tlc and what is the difference travelled between the component and solvent called
The strength of the intermolecular forces and its known as retention factor
State why in thin layer chromatography
Why gloves are worn
Why the line is drawn in pencil
Why the Tlc plate is sealed with a lid
Why it’s dried in a fume cupboard
Plastic gloves are worn to prevent contamination
Pencil is used to draw the line so it won’t dissolve and run
It’s sealed with a lid to prevent evaporation of the toxic solvent
It’s dried in a fume cupboard as the solvent is toxic
Tiny drops are used as a large drop will cause spots to merge
