During my six-odd years as a graduate organic chemist, probably the cheapest, most powerful, and most commonly used analytical laboratory technique in my bag of tricks was thin-layer chromatography. Explaining chromatography theory is a big job, but the idea boils down pretty well to this: chromatography is the art of taking a complex mixture with all sorts of compounds in it and separating them out one at a time.
There are a couple of reasons you might want to do this: First, because you only want one of those compounds and need to purify it by getting rid of the rest. This is called “preparative” chromatography and it is a complex and relatively expensive endeavor. But the other common reason for performing separations is analytical: You want to get an idea of how many compounds are in there and whether or not one of them is compound “X.” Thin-layer chromatography lets you do this, on a bench-top, with a few cents worth of materials and a few minutes of time. It’s unbelievably powerful for such an inexpensive technique, and Science Project Lab has a great tutorial on getting started at home.
4 thoughts on “Thin layer chromatography in the kitchen”
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I tried this in endless sessions at home when I was a kid. I even ground glass as stationary phase. The problem with all homemade DC plates is, that they don’t work that great. Usually the performance does not exceed filter paper. The surface of readily available powders is just too small. Also usually the surface gets quite some cracks making it hard to analyse the plates with a PC and the plates can not be stored as touching them causes the powder to come off. I would rather recommend using eihter filter paper and concentrate on the proper liquid phase or buy the DC plates. Commercial plates, usually sold in boxes of 50 for around 30 Dollar, give you awesome results. Just try to split chlorophyll on a home made plate and compare to a commercial plate. The difference is staggering! Today I only use HPLC and GC in the lab anymore :-)
Nice to hear from someone who’s actually tried the homebrew approach. Thanks for your comment.
What you say about the surface area of the solid phase is well taken; I did some experiments of my own a couple years ago with using Portland cement as the stationary phase, and I have to admit the results were not good.
Buying commercial TLC plates is a great idea so long as one understands the potential dangers of working with silica and how to prevent them. On a small, homebrew scale, these dangers are slight, but they should be acknowledged.