Flashcards in Practicals Deck (10)
What is chromatography?
separating mixtures of coloured compounds
What are the paper or thin layer of absorbent material examples of?
what is the solvent?
the mobile phase
describe the chromatography method?
- add the concentrated spot of mixture to the stationary phase
- end of stationary phase is suspended in the solvent (mobile phase)
- pigments/compounds move different distances according to their solubility
- if compounds aren't visible a stain is required
- end before solvent front reaches the end of the stationary phase
How do you calculate Rf values?
Rf = distance moved by compound/distance moved by solvent
what is the Rf value always less than?
what does it mean if the Rf value is higher?
the higher the Rf value, the more soluble the compound is in the solvent
What colour change does DCPIP undergo when reduced?
blue --> colourless
What does DCPIP replace?
DCPIP replaces NADP as the electron acceptor in the LDR
the rate of colour change is proportional to the rate of the LDR and the amount of DCPIP formed