Talk:Mikhail Tsvet

message: His last name hints that his father could have been baptized Jew, but I cannot find any info. Mikkalai 04:38, 28 Oct 2004 (UTC)
thread_title: Untitled

message: There is any such taxon?--Penarc (talk) 03:02, 18 April 2008 (UTC)
thread_title:  plant described 

message: I stumbled upon an article which states that Tsvet is not the inventor of chromatography: Click here JefVG (talk) 09:48, 15 July 2008 (UTC)
thread_title:  Tsvet is NOT the inventor of chromatography 

message: Since he was born in Italy to an italian woman he should be considered italian/russian or russian/italian.  — Preceding unsigned comment added by 93.32.56.195 (talk) 17:08, 21 January 2012 (UTC)
thread_title: Russian

message: At present, the article states:
Mikhail Tsvet invented chromatography in 1903 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.
So, Tsvet invented chromatography in 1903 -- after describing the method at a meeting in 1901?
Cwkmail (talk) 23:10, 9 July 2014 (UTC)
thread_title: Date of discovery of chromatography?

message: At present, the article states:  "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."
Many other sources repeat this claim.  However, I've read the relevant papers by Willstätter and Tsvet, and I've noticed that both investigators used calcium carbonate in their chromatographic analyses of chlorophyll.  So the difference in outcomes could not be due to "an overly aggressive adsorbent" which destroyed the chlorophyll.  Although in his 1912 paper[1] Willstätter attributed the difference in outcomes to Tsvet's supposed use of "alcohol" (ethanol) during his analyses of chlorophyll — Willstätter had found in 1911 that ethanol degraded chlorophyll — it seems more likely that Willstätter and Stoll's chromatographic analyses of chlorophyll produced results that differed from Tsvet's results because of the presence of water. 
In their paper of 1912, Willstätter and Stoll stated that chlorophyll samples turned brown when they came into contact with the calcium carbonate of their chromatographic columns, whereas Tsvet made no such observations regarding his chromatographic analyses of chlorophyll.  In his papers of 1906, Tsvet mentions that the calcium carbonate must be dried in an oven.   And in his paper of 1910 — M. Tswett (1910) "Das sogenannte "krystallisierte Chlorophyll" — ein Gemisch" (The so-called "crystallized chlorophyll" — a mixture), Berichte der deutschen chemischen Gesellschaft, 43 :  3139–3141. — Tsvet used non-polar solvents to elute his columns.  So Tsvet was aware that the presence of water might cause calcium carbonate to degrade a sample.
In summary, in their paper of 1912 (and in subsequent publications) Willstätter and Stoll used the same adsorbent (calcium carbonate) as Tsvet had used in his chromatographic analyses of chlorophyll.  Although Willstätter and Stoll accused Tsvet of having exposed his chlorophyll samples to ethanol (which would have degraded them), it's more likely that Willstätter and Stoll's materials had been contaminated by water, whereas Tsvet's materials hadn't — which would explain why Willstätter and Stoll's chlorophyll samples turned brown when they came in contact with the calcium carbonate adsorbent, whereas Tsvet's samples didn't change color.
I would therefore suggest that the sentence be rewritten as:  "Richard Willstätter and Arthur Stoll tried to repeat Tsvet's experiments, but were not able to do so."
[1] Willstätter, Richard and Stoll, Arthur (1912) "Untersuchungen über Chlorophyll:  XIX. Über die Chlorophyllide" (Investigations of chlorophyll:  19.  On chlorophyllide), Annalen der Chemie, 387 :  317–386.
VexorAbVikipædia (talk) 16:08, 30 September 2016 (UTC)
thread_title:  Willstätter's failure to reproduce Tsvet's results