Experiment 3 spinach

procedure for spinach

1. add spinach, mgs04 and sand to make a mixture

2. transfer for a test tube and add 2 ml of acetone, stir and let set for 10 minutes after covering

3. create tlc chamber with 70% ethyl acetate and 30% hexane

4. compare spinach tlc to beta carotene, chlorophylls a and b

why is acetone used?

Acetone is:

• Polar enough to dissolve chlorophyll

• Nonpolar enough to dissolve β-carotene

• Good at penetrating plant tissue

It extracts the pigments into solution.

What is the mobile phase?

a tlc phase in which the sample mixture is places in a gas or liquid phase

which substance in spinach is the most non polar / most polar?

most non polar = beta carotene most polar = chlorophyll b

What is the stationary phase?

the sample is carried by the mobile phase through the stationary phase which consists of a solid support aht contains an adsorbent

What do the components of the sample mixture pass through the stationary phase as?

bands

What adsorbent for the stationary phase is typically used?

silica gel or alumnina W

Why is silica gel or alumina typically used?

have many sites for H bonds

What is the solvent that is used for the mobile phase called?

eluent

What is the rf value for polar compounds?

small

What is the rf value for non polar compounds

large rf close to 1

what is rf formula?

distance from origin to spot / distance from origin to solvent front

Which eluent gave the best separation?

70 ethyl acetate and 30 hexane

Making an eluent more polar does what?

increases distance traveld by bands

Making an eleunt more non polar

decrease distance traveled by bands