Deuterium vs. Tritium - (Apr/04/2006 )
Which is the main difference among deuterium and tritium labeled compounds in metabolic research?
Deuterium behaves chemically identically to ordinary hydrogen, although, because of the greater atomic mass, reactions involving deuterium tend to occur at a somewhat slower reaction rate than the corresponding reactions involving ordinary hydrogen. The two isotopes can be distinguished physically by using mass spectrometry. In addition, the physical properties of deuterium compounds can be different than the hydrogen analogs; for example, D2O is more viscous than H2O. The deuteron has spin +1 thus it is a boson.
Tritium (symbol T or 3H) is a radioactive isotope of hydrogen. The nucleus of tritium (sometimes called triton) contains one proton and two neutrons, whereas the nucleus of protium (the most abundant hydrogen isotope) contains no neutrons. Its atomic weight is 3.0160492. It is a gas (T2 or 3H2) at standard temperature and pressure. Tritium combines with oxygen to form a liquid called tritiated water T2O or partially tritiated THO.
Tritium is radioactive with a half-life of 12.32 years. It decays into helium-3 by the reaction
these are 2 extracts of wikipedia.
It explains the main difference : radioactive or not.