How is Column Chromatography Useful?
Eleanor Roosevelt High School, Manhattan
Summer Research Program for Science Teachers
Student Learning Outcomes:
SWBAT define what column chromatography is and relate how it is used.
SWBAT isolate spinach pigments from frozen spinach.
eluent (commercially purchased)
mortar & pistil
Having not been exposed to chromatography columns, students will get a sneak peek to an advanced form of purification techniques. Secondly, isolating pigments from spinach is new for students. The process alone is the motivational tool.
Description of Instructional Procedure:
Students will assemble their columns: cotton, sand, silica gel.
The spinach will be ground in the mortar and pistil with some ethanol until the acetone has enough pigment in it (should be a dark green).
A piece of cotton is then placed in the acetone to soak up some of the spinach pigment and it is then placed in the column.
Eluent is poured over the cotton and separation occurs.
An orange band will appear first.
Collect the pigments with test tubes.
Students will clean their benches and dispose of the chemicals in the proper waste bins.
Students will submit a lab report the following week in order to report their findings. Some of the questions to be answered:
Why did the orange pigment separate first?
Did the eluent have anything to do with this phenomena?
How can you improve on this experiment?
How does chromatography help scientists identify chemicals?
How does column chromatography relate to other identification techniques?
New York State Learning Standards:
A: Science as Inquiry- Students should develop the abilities necessary to do and understand scientific inquiry.
B: Students should develop an understanding of investigating the structure and properties of atoms and molecules as well as chemical reactions.
G1, G2: Science as a human endeavor, Nature of scientific knowledge (respectively).