American chemist (1913?1943)
For the Duracell founder and mercury cell developer, see
Samuel Ruben
.
For the KTLA entertainment reporter, see
Sam Rubin
.
Samuel Ruben
(born
Charles Rubenstein
; November 5, 1913 ? September 28, 1943) was an American chemist who with
Martin Kamen
co-discovered the
synthesis
of the
isotope
carbon-14
in 1940.
Early life
[
edit
]
Ruben was the son of Herschel and Frieda Penn Rubenstein ? the name was officially shortened to Ruben in 1930. Young Sam developed a friendship with neighbor
Jack Dempsey
and became involved with a local boys' boxing club and later, when the family moved across the Bay to
Berkeley
, he was a successful basketball player at
Berkeley High School (Berkeley, California)
. After achieving his B.S. in
chemistry
at the
University of California, Berkeley
, he continued his studies there and was awarded a Ph.D. in
physical chemistry
in May 1938. He was immediately appointed instructor in the chemistry department, and became an assistant professor in 1941.
[
citation needed
]
Research
[
edit
]
Ruben and colleague
Martin Kamen
, a
University of Chicago
Ph.D. and researcher in chemistry and
nuclear physics
working under
Ernest O. Lawrence
at the
Berkeley Radiation Laboratory
, set out to elucidate the path of carbon in
photosynthesis
by incorporating the short-lived radioactive isotope
carbon-11
(
11
CO
2
) in their many experiments between 1938 and 1942. Aided by the concepts and collaboration of
C. B. van Niel
, at
Stanford University
's
Hopkins Marine Station
, it became clear to them that reduction of
CO
2
can occur in the dark and may involve processes similar to bacterial systems. This interpretation challenged the century-old
Adolf von Baeyer
theory of photochemical reduction of CO
2
adsorbed on
chlorophyll
which had guided decades of effort by
Richard Willstatter
,
Arthur Stoll
, and many others in vain searches for
formaldehyde
.
In hundreds of experiments with carbon-11 produced from
deuterons
and boron-10 by Kamen in the Radiation Laboratory's 37-inch
cyclotron
, Ruben and Kamen, with collaborators from
botany
,
microbiology
,
physiology
and
organic chemistry
, pursued the path of carbon dioxide in plants, algae, and bacteria. Their results, confused by absorption of the products on proteinaceous residues, initially failed to reveal the path of carbon in photosynthesis but succeeded in exciting the interest of scientists worldwide in the search and revelation of metabolic processes, beginning a revolution in
biochemistry
and medicine.
Ruben's experiments using 'heavy water',
H
2
18
O
, to yield
18
O
2
gas had shown that the
oxygen
gas produced in photosynthesis comes from water. With nuclear physicists' tenuous prediction of a "long-lived radioactive carbon isotope", Ruben and Kamen pursued several routes that could lead to identification of the
carbon-14
isotope. After several failed attempts, Kamen collected the results of a 120-hour
cyclotron
bombardment of graphite and trudged in the rain with it to the "Rat House", adjacent both to the chemistry department and to the
cyclotron
, and Ruben's desk. At 8 am, February 27, 1940, Ruben demonstrated unequivocally that the radioactivity was from carbon-14.
[
citation needed
]
Use of carbon-14 in tracer experiments was hindered by the difficulty measuring the weak beta emission of the radioactive decay and by the onset of World War II that shut off production of the isotope. In 1942 Ruben was assigned to work on war related research away from Berkeley. Further, Kamen was removed from his position at Berkeley due to allegations he was a security risk. Ruben fully realized the potential use of this isotope and was committed to working to elucidate the mechanism of photosynthetic carbon fixation using carbon-14. Instead, Ruben gave all his barium carbonate-
14
C to chemistry department faculty member
Andrew Benson
who began his long series of
14
CO
2
fixation experiments to determine the path of carbon in photosynthesis. Only in 1949 did chemist
Willard Libby
use it to invent
radiocarbon dating
.
Ruben's recruitment for research in the World War II wartime effort led him to interest in the mechanism of
phosgene
as a poisonous gas. With C-11 phosgene (
11
COCl
2
) prepared by Benson, they studied the combination of phosgene with lung proteins. Following Benson's departure from Berkeley in July 1943, Ruben died September 28, 1943, after a disastrous exposure to phosgene in a laboratory accident the preceding day.
Sam Ruben married Helena Collins West, a fellow chemistry student, during his final semester as an undergraduate at UC Berkeley, on September 28, 1935. They had three children: Dana West Ruben (born November 11, 1938), George Collins Ruben (born April 29, 1941), who became a professor at
Dartmouth College
,
[1]
and Connie Mae Ruben Fatt (born June 18, 1943).
References
[
edit
]
Sources
[
edit
]