Chromatography Flashcards
What is chromatography used for?
-used to separate a mixture into it’s individual components
-relies on different solubilities of different chemicals in a mixture
How does chromatography work?
-components separate as the mobile phase travels over the stationary phase
-higher solubility = travels further up
Method of putting mixture on paper
-spots of mixture are placed on paper
-left to dry
-suspended in a solvent
-as solvent travels up paper - different components move up paper at different speeds
-causes OG mixture to separate into different spots = chromatogram
Separating monosaccharides
-mixtures already coloured don’t have to be stained
-spot is placed on the line - known spots are placed next to the sample
-suspended in a solvent
-unknown can be identified by comparing + matching with known solutions
Separating amino acids
-spots of unknown placed to known
-known = lysine, alanine + methionine
-paper is suspended
-separate different distances - depending on charge + size
-can be compared to known
-same distance = contain this amino acid
How to work out RF value?
-line drawn to show how far solvent has travelled from solvent front
-Rf value = how far a dissolved molecule travels during its mobile phase
What does a smaller Rf value mean?
-smaller = less soluble - larger in size
Rf value equation
-distance moved by solute/distance moved by solvent
Identifying chloroplast pigments
-carotenoids = highest value
-chlorophyll B = lower Rf
-chlorophyll A = Rf between B + C