Column Chromatography - Pre-Lab

The ABSOLUTELY ROUTINE way to purify mixtures of compounds. It is TEDIOUS, but EFFECTIVE. I have run THOUSANDS of them.

In short, you have to PACK a column - introducing silica gel and equilibrating it with some eluent. There's some dispute as to what "best practices" are here - there are pros and cons to all methods.

Then you DISSOLVE the sample to be separated (or rotavap it onto silica gel if you are going to dry-load it.).

Then you LOAD the sample.

Then you ELUTE the sample, often by starting with a LOW polarity eluent, eventually raising the polarity higher to elute more polar compounds - collecting the eluent into MULTIPLE different fractions (test tubes in this case).

Then you perform TLC on the fractions in order to find out which fractions contain the desired material.

Once all fractions of desired material have been identified, you combine them into a round-bottom flask and "rotavap" - evaporating the solvent off.

Timestamps -
0:00 - Flash Chromatography - with gas
0:27 - Flash column (manual squeeze bulb)
0:51 - To prepare for a column you must decide on an eluent by TLC
4:38 - The DRY packing method
6:34 - If DRY packing, you eventually EQUILIBRATE
7:07 - WET packing equilibrates immediately, but is MESSY
8:27 - DJS preferred method. Less messy, needs to be equilibrated
9:31 - Using the gas to force through
10:06 - Dissolving the glop to be separated and Loading it
11:03 - To Sand or NOT to sand?
11:19 - Running the initial eluent
12:19 - Overshot a hair. OOPS.
13:03 - Next slug of eluent.
13:39 - Column over, Where's the STUFF?
14:23 - TLC of fractions
15:17 - Multiple plates in the chamber!
15:38 - UV light - where's the stuff?
16:40 - THIS is WHY we CAM stain!
17:42 - Rotavapping!