Mikhail Tsvet

Mikhail Semyonovich Tsvet, also spelt Tsvett, Tswett, Tswet, Zwet, and Cvet (Russian: Михаил Семёнович Цвет; 14 May 1872 – 26 June 1919) was a Russian-Italian botanist who invented chromatography. His last name is Russian for "colour" and is also the root word of "flower."

Biography
Mikhail Tsvet was born on 14 May 1872 in Asti, Italy. His mother was Italian, and his father was a Russian official. His mother died soon after his birth, and he was raised in Geneva, Switzerland. He received his BS degree from the Department of Physics and Mathematics at the University of Geneva in 1893. However, he decided to dedicate himself to botany and received his PhD degree in 1896 for his work on cell physiology. He moved to Saint Petersburg, Russia, in 1896 because his father was recalled from the foreign service. There he started to work at the Biological Laboratory of the Russian Academy of Sciences. His Geneva degrees were not recognized in Russia, and he had to earn Russian degrees. In 1897 he became a teacher of botany courses for women. In 1902 he became a laboratory assistant at the Institute of Plant Physiology of the Warsaw University (now in Poland). In 1903 he became an assistant professor and taught also at other Warsaw universities. After the beginning of World War I, the Warsaw University of Technology was evacuated to Moscow, Russia, and in 1916 again to Gorki near Moscow. In 1917 he became a Professor of Botany and the director of the botanical gardens at the University of Tartu (Yuryev) (now in Estonia). In 1918 when German troops occupied the city, the university was evacuated to Voronezh, a large city in the south of Central Russia. Tsvet died of a chronic inflammation of the throat on 26 June 1919 at the age of 47.



Chromatography
Mikhail Tsvet invented chromatography in 1900 during his research on plant pigments. He used liquid-adsorption column chromatography with calcium carbonate as adsorbent and petrol ether/ethanol mixtures as eluent to separate chlorophylls and carotenoids. The method was described on 30 December 1901 at the XI Congress of Naturalists and Physicians (XI съезд естествоиспытателей и врачей) in St. Petersburg. The first printed description was in 1905, in the Proceedings of the Warsaw Society of Naturalists, biology section. He first used the term "chromatography" in print in 1906 in his two papers about chlorophyll in the German botanical journal, Berichte der Deutschen botanischen Gesellschaft. . On page 322, Tsvet coins the term "chromatography": Original : "Wird eine petrolätherishe Chlorophyllösung durch eine Säule eines Adsorptionsmittels durchfiltriert (ich verwende hauptsächlich Calciumcarbonate, welches in engen Glasröhren dicht gestampft wird), so werden die Farbstoffe gemäss der Adsorptionsreihe von oben nach unten in verschieden gefärbten Zonen auseinandergelegt, indem die stärker adsorbierten Farbstoffe die schwächer zurückgehaltenen weiter nach unten verdrängen.  Diese Trennung wird praktisch vollständig, wenn man nach dem Durchgange der Farbstofflösung durch die adsorbierende Säule einen Strom des reinen Lösungsmittels herstellt.  Wie die Lichtstrahlen im Spektrum, so werden in der Calciumkarbonatsäule die verschiedenen Komponenten eines Farbstoffgemisches gesetzmässig auseindergelegt, und lassen sich darin qualitativ und auch quantitativ bestimmen.  Ein solches Präparat nenne ich ein Chromatogramm und die entsprechende Methode, die chromatographische Methode." Translation : If a solution of chlorophyll in petroleum ether is filtered through a column of an adsorbent (I use mainly calcium carbonate, which is tamped firmly in narrow glass tubes), then the pigments are dispersed, according to the adsorption series, from top to bottom in differently coloured zones, by the more strongly adsorbed pigments' displacing farther downwards the more weakly retained ones. This separation is practically complete when one establishes a flow of pure solvent behind the passage of the pigment solution through the adsorbing column. Like light rays in a spectrum, so the different components of a mixture of pigments are dispersed in the calcium carbonate column following a set pattern, and [they] can be determined in there qualitatively as well as quantitatively. I call such a preparation a "chromatogram" and the corresponding method, the "chromatographic method". In 1907 he demonstrated his chromatograph for the German Botanical Society.

For several reasons, Tsvet's work was long ignored: the violent political upheaval in Russia at the beginning of the 20th century, the fact that Tsvet originally published only in Russian (making his results largely inaccessible to western scientists), and an article denying Tsvet's findings. Richard Willstätter and Arthur Stoll tried to repeat Tsvet's experiments, but because they used an overly aggressive adsorbent (destroying the chlorophyll), were not able to do so. On pages 323–324, Willstätter and Stoll state their objections to Tsvet's chromatographic methods: ''"Die chromatographische Adsorptionsanalyse, die in den Händen von M. Tswett1) zu wichtigen Resultaten hinsichtlich des Chlorophylls und seiner Derivate geführt hat, halten wir für die Arbeit in größerem Maßstab, also für präparative Zwecke nicht für brauchbar. Die freien Chlorophyllide sind zu unbeständig ; ihre Farbe schlägt leicht in braun um, wenn sie von Adsorbentien aufgenommen werden. Aber selbst die Methylchlorophyllide sind zu empfindlich, so daß es noch weiter Verbesserungen2) des Tswettschen Verfahrens bedarf, um sie nach diesem wieder unverändert zu isolieren.  Beim Adsorbieren mit Calciumcarbonat und beim Ausziehen mit Alkohol unterliegen alle Chlorophyllide, wie wir in unseren letzten Arbeiten beschreiben haben1), leicht der Umwandlung, die sich bei der Verseifung mit Alkalien durch Auftreten schwach basischer Phytochlorine und Phytorhodine verrät. Es ist noch nicht bekannt, ob bei der Tswettschen Adsorptionsanalyse in kleinem Maßstab diese Veränderung der Magnesiumverbindungen vermieden worden ist."'' (Chromatographic adsorption analysis, which in the hands of M. Tsvet has led to important results regarding chlorophyll and its derivatives, we hold to be unsuitable for work on a larger scale, thus, for preparative purposes. Free chlorophyllides are too unstable ; their colors turn brown readily when they are adsorbed. But even methylchlorophyllides are too sensitive, so that still further improvements of Tsvet's method are needed in order to isolate them unchanged by this [method]. During adsorption by calcium carbonate and during extraction with alcohol, all chlorophyllides succumb, as we described in our latest articles, readily to the transformation, which betrays itself during hydrolysis with alkalies by the appearance of weakly basic phytochlorine and phytorhodine. It's still not known whether in the case of Tsvet's adsorption analysis ([which functions] on a small scale), this change of the magnesium compounds has been avoided.) They published their results and Tsvet's chromatography method fell into obscurity. It was revived 10 years after his death thanks to Austrian biochemist Richard Kuhn and his student, German scientist Edgar Lederer   as well as the work of A. J. Martin and R. L. Synge.

Botanical author abbreviation
The standard botanical author abbreviation Tswett is applied to plants that he described.