RP12- Chromatography Flashcards
How do you calculate Rf values?
distance travelled by component/distance travelled by solvent
What is TLC used for?
to separate a mixture into its components for analysis
How do you carry out TLC?
- add solvent to jar and seal
- draw pencil line, spot samples along this
- add TLC plate and ensure solvent below jar. leave for a period of time
- draw line where solvent finishes
Why is the jar sealed?
create a saturated environment
Why must lines on the TLC plate be drawn in pencil?
as if drawn in ink, ink would dissolve in the solvent and run up the plate
Why does the solvent have to be below the start line?
as otherwise solvents would dissolve and would not be carried up the plate
What happens if the sample is too concentrated?
spots overlap
what happens if you use large base line and less solvent?
larger spots
How do you view spots on a TLC plates?
UV lamp
What causes organic compounds to have a greater retention time?
- more polar
- greater affinity TO THE STATIONARY PHASE
What chemical can be used to develop amino acid TLC plates?
Ninhydrin
