Being Creative in the Lab: The cutest Start-Spot Chromatography Column ever!

Ever heard about Colum Chromatography? If not, than have a quick look at the general principle, which was briefly presented by @mcw. It is also closely related to Thin Layer Chromatography or TLC, another topic he discussed earlier.

Building upon this I would like to share some funny 'purification setup', which I was needed to use in the lab lately:

The smallest and cutest Chromatography Column

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Tiny Chromatography Column: Pasteur Pipette, Cotton & Silica Gel

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I was challenged to selectively convert a certain sec. alcohol into an ketone functionality. For this I used the so-called TPAP oxidation, which works with Tetrapropylammonium perruthenate ('TPAP') as an oxidation catalyst and N-Methylmorpholine N-oxide ('NMO') as the actual oxidant:

^{Reaction drawn with ChemSketch freeware}

After performing the oxidation step testwise on a microgram scale, I had to analyze the reaction mixture, what required the separation of the catalyst. Since the catalyst is an ionic species, it has enormously strong interaction with the silica gel used as the column material.

This means that the black catalyst did not pass through the tiny column, but got stuck as a black ‘start spot’ right at the beginning of it, rendering this separation more filtration like rather than classical chromatography. Only the other chemical species of the reaction mixture were quickly flushed through the column. So I was able to prepare my mini reaction mixture for analysis with not even five minutes of work.

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I hope you enjoyed today's 'tiny’ lab-experience sharing.

Best,
mountain.phil28