Lecture 14
• IR & 1H NMR Practice Problem (Lec 13)
• Column Chromatography of Plant Pigments
• Get Lecture Problem 5, due next class
This Week In Lab:
• Ch 7 PreLab Due
• Quiz 4
• Ch 5 Final Report Due
Next Week in Lab:
• Ch 9 PreLab Due
• Quiz 5
• Ch 6 Final Report Due
2. T his c ompound has t he formula C 5 H10O. Det ermine it s s tr uct ur e by u sing t he
following spec tr al da t a.
QuickTime™ anda
TIFF(LZW) decompressor
are needed to seethis picture.
Chapter 9
Column Chromatography of Plant Pigments
A two-day experiment
Day One - Extraction & Chromatography of Plant Pigments
Day Two - UV/Vis Analysis of Plant Pigments
Extraction of Plant Pigments
• Obtain spinach leaves
• Grind up leaves with acetone, petroleum ether and CaCO3
• Transfer to a separatory funnel
• Extract (similar to Ch 5!)
• Organic layer contains plant pigments - to be separated via
column chromatography
Column Chromatography of Plant Pigments
• Pack column
• Load sample (plant pigment solution/organic layer) to column
• Run column & collect fractions in tared flasks
**NEVER let the column to dry**
Always have fresh mobile phase in the column
• TLC the fractions
See video on column prep in class.
Column Chromatography
Of Plant Pigments:
Getting the column ready
Step 1
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
http://www.uni-regensburg.de/Fakultaeten/nat_Fak_IV/Organische_Chemie/Didaktik/Keusch/D-CC-e.htm
What the column will look
like - the colored bands
are the plant pigments!
Running the column &
collecting fractions
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
http://www.uni-regensburg.de/Fakultaeten/nat_Fak_IV/Organische_Chemie/Didaktik/Keusch/D-CC-e.htm
The different fractions
That contain the
Different pigments
Finishing up &
Evaluating the fractions
Evaluate by TLC &
By UV/Vis
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
http://www.uni-regensburg.de/Fakultaeten/nat_Fak_IV/Organische_Chemie/Didaktik/Keusch/D-CC-e.htm
Carotenoids
CH 3
CH 3 H
• Hydrocarbons
C
C
CH 3 H
CH 3 H
C
C
CH 3 H
CH 3
• Orange/red/yellow
pigments in fruits and
veggies
C
H
C
C
H
C
H
C
C
H
H
C
H
C
C
C
H
C
CH 3 H
C
H
C
CH 3
C
CH 3 H
CH 3
lycopene C 40 H 56 - m.p. 173°C (all trans)
CH 3 H
CH 3 H
C
• Conjugated p systems
C
CH 3H
C
C
H
C
CH 3
C
C
H
C
H
CH 2OH
CH 3
Vitamin A C 20 H 30 O
• Involved in
photosynthesis
CH 3 H
C
C
CH 3H
CH 3
CH 3 H
C
C
H
C
CH 3 H
C
H
C
C
H
C
C
H
H
C
C
H
C
C
CH 3 H
H
C
CH 3
HCH
3
C
C
C
CH 3 H
-carotene C40 H 56 - m.p. 183°C (all trans)
CH 3
Chlorophylls
• Porphyrins
• Blue/green pigments in plant leaves
• Also involved in photosynthesis
• Produced by plants in response to sunlight
CH 2
CH
N
H3C
O
CH 3
N
CH 2
CH 2CH 3
H3C
N
H
C
N
H 3C
Mg
CH
H
N
CH 2CH 3
Mg
CH 3
N
H3C
N
H
H
CH 3
N
H
CH 2
CH 2
O
COOCH 3
CH 3
CH 2COOCH 2
O
COOCH 3
CH 3
CH 2COOCH 2
CH 3
chlorophyll-a
CH 3
CH 3
CH 3
CH 3
chlorophyll-b
CH 3
CH 3
CH 3
Flavonoids
• Aromatic compounds
• Red, violet, blue, or yellow pigments in plants, fruit, flowers
• In fruit and flowers, act as an attractant for insects to distribute pollen
and seeds
• In leaves, act as sunscreens
OH
OH
HO
O
O
OH
O
Luteolin
O
Anthocyanin
Gly