Svedberg, Theodor (1884–1971)

Swedish chemist. In 1923 he constructed the first ultracentrifuge, a machine that allowed the rapid separation of particles by mass. This can reveal the presence of contaminants in a sample of a new protein, or distinguish between various long-chain polymers. He was awarded the Nobel Prize for Chemistry in 1926 for his investigation of dispersed systems.

Svedberg was born near Gävle, studied at Uppsala and spent his career there, as professor 1912–49 and head of the Institute of Nuclear Chemistry 1949–67.

Svedberg prepared a number of new organosols from more than 30 metals. Through an ultramicroscope, he studied the particles in these sols and confirmed Albert Einstein's theories about Brownian movement.

Svedberg discovered that thorium-X (now known as lead-208) crystallizes with lead and barium salts (but not with others), anticipating English chemist Frederick Soddy's demonstration of the existence of isotopes.

Svedberg also investigated, about 1923, the chemistry involved in the formation of latent images in photographic emulsions.

Working on synthetic polymers, Svedberg introduced electron microscopy to study natural and regenerated cellulose, X-ray diffraction techniques to investigate cellulose fibres, and electron diffraction to analyse colloidal micelles and crystallites.