Chromatography Flashcards
what is the aim of chromatography?
to separate different molecules/ components into its constituents
what is the stationary phase?
phase that doesn’t move e.g chromatography paper(cellulose) or TLC
What is a TLC plate often made from?
silica gel and plastic sheet
explain why the stationary phase is polar?
paper is highly polar it has exposed OH groups so some polar molecules form hydrogen bonds with paper and so move more slowly
what is the mobile phase
the phase that moves e.g the solvent, water for polar molecules and ethanol non polar molecules
why do molecules move up the stationary phase?
the mobile phase moves through the stationary phase carrying molecules to be separate
stationary in amino acid chromatography what is the phase?
the chromatography paper
what is the speed of movement of biological molecules and so the distance travelled proportional to?
-solubility of molecules
-polarity
-size of molecule
if paper is highly polar will a molecule move more slowly or quickly compared to a non polar molecule?
more slowly, the molecule will form hydrogen bonds with the paper
what do you do if 2 molecules travel at the same speed what can u do to separate them?
use a different solvent
how do you use the Rf value to identify molecules from chromatograpy?
distance moved by compound/ distance moved by solvent
describe 3 ways to detect the biological molecules separated using chromatrography?
-UV light
-ninhydrin
-iodine
