Tswett, Mikhail Semyonovich (1872–1919)

Italian-born Russian botanist who made an extensive study of plant pigments and developed the technique of chromatography to separate them, in 1906.

Tswett was born in Asti and studied at Geneva, Switzerland. He worked in Warsaw from 1901, and during World War I organized the evacuation of the Botany Department of the Warsaw Polytechnic Institute to Moscow and Gorky. In 1917 he was appointed professor of botany at Yuriev University (Estonia), but under threat of German invasion had to move once again, to Voronezh.

Tswett showed that green leaves contain more than one type of chlorophyll, and by 1906 he had devised an adsorption method of separating the pigments. He ground up leaves in petroleum ether and let the liquid trickle down a glass tube filled with powdered chalk or alumina. As the mixture seeped downwards, each pigment showed a different degree of readiness to attach itself to the absorbent, and in this way the pigments became separated as different-coloured layers in the tube. Tswett called the new technique chromatography because the result of the analysis was ‘written in colour’ along the length of the adsorbent column. Eventually he found six different pigments.