Mikhail Tsvet got interested in the nature of chlorophyll – the substance that makes leaves green. The role of this substance in nature is enormous: with its help, the solar energy absorbed by a leaf is converted into chemical energy of organic compounds.
Professor Tsvet filled a glass tube with finely ground powder of pure chalk, damped it with benzene, and then poured over a little bit of chlorophyll solution extracted from a fresh leaf. The very top layer of the powder was, of course, immediately colored green, and then Tsvet proceeded to slowly, drop by drop, add benzene, into the tube filled with chalk. As colored layer got rinsed out with benzene, the green band started to move down the tube following the solvent. Then (this, in fact, was Tsvet’s remarkable discovery) the band started to slowly separate. There was a narrow yellow band that moved the slowest along the tube, it was preceded by the yellow-green one, and in front of it there was a wide, green-blue band, followed by two yellow ones, and finally, at the very bottom, there was one more band, also of yellow color. Thorough analysis showed, that above the top yellow band there was also one more – a colorless one. With his experiment, Tsvet proved that chlorophyll had a complex structure, and this work laid the foundation to a new science.
The components of a substance, just like the light rays in the spectrum, positioned themselves one after another in the column of powder in the form of colored bands. This phenomenon was named chromatogram and the test method – chromatography, from the Greek words “chromo” – color, “gamma” – read, and “graph” – write.