Radioactive hydrogen

Table II shows that 100% of the hydrogen sulfide produced by sulfur -dusted fruit was derived from the sulfur applied, 11% from the sulfur dioxide treated fruit, and 5% from the sulfuric acid treated fruit. Thus, the higher the state of oxidation of the sulfur applied, the more limited the production of radioactive hydrogen sulfide. No hydrogen sulfide was obtained from the controls.

Reaction Using Radioactive Hydrogen as a Tracer. J. Amer. chem. Soc. 64, 2294 (1942). 

Water is a mixture of varying isotopic composition (Franks, 2000). In addition to the two most common isotopes, 160 and there are two stable oxygen isotopes (170, lsO), one stable hydrogen isotope (2H, deuterium), and one radioactive hydrogen isotope (3H, tritium, half-life = 12.6 years). Water also contains low concentrations of hydronium (H30+) and hydroxide ions (OH-) and their isotopic variants. In total, water consists of more than 33 chemical variants of HOH however, these variants occur in relatively minor amounts (Fennema, 1996). Table II gives the natural abundance isotopic composition of the four major water species. 

D—deuterium, heavy stable hydrogen, 1 proton + 1 neutron T—tritium, radioactive hydrogen, 1 proton + 2 neutrons... 

All cases of radioactive decay involve the atom s nucleus. Since these processes do not involve the atom s electrons, they occur regardless of the chemical environment of the nucleus. For example, radioactive hydrogen-3, or tritium, will decay by (1 particle emission whether it is contained in a water molecule or hydrogen gas, or in a complex protein. 

D. Harman, T.D. Stewart, and S. Ruben, A Study of the Menschutkin reaction Using Radioactive Hydrogen as a Tracer, Journal of the American Chemical Society 64, 2294-2296, 1942. 

T. H. Norris, S. Ruben, and M.B. Allen, Tracer Experiments with Radioactive Hydrogen. Some Experiments on Photosynthesis and Chlorophyll, Journal of ihe American Chemical Society 64, 3037-3050, 1942. 

Although the most common label is still the radioactive hydrogen or iodine atom, the problems associated with radioactivity have led to a continual search for other techniques that may be in some ways preferable to it. Fluorescence, in principal, can be detected with the same sensitivity as radioactivity however, unlike radioactivity, there is a very significant natural background fluorescence in biological material. A variety of procedures have been called on to get around this problem (15), and some of these have made their way into commercial instrumentation. 

Boron in the form of boric acid may be added to the primary coolant which also serves as a further moderator and together with added lithium hydroxide controls the corrosivity of the primary coolant towards the system components. The hydroxide of the lithium seven isotope ( Li) is used for pH control of the primary coolant since any appreciable amounts of Li isotope produces the gaseous highly radioactive hydrogen isotope tritium ( H) by neutron capture ... 

Almost only fairly long-lived radioisotopes, mostly weak )5-emitters, have been used in chemical and biological investigations. Radiocarbon, C(half-life 5568 years, maximum energy 0.155 mev) and radioactive hydrogen, H(tritium) (half-life 12.26 years, maximum energy 0.018 mev) are particularly important. Radioactive phosphorus, P(14.2 days, 1.71 mev), sulphur, S(87.1 days, 0.167 mev) and iodine, H(8.04 days, 0.608 mev(j5) and several p- and y-radiations) have also often been used. 

Tritium (IP or T) is a radioactive hydrogen isotope of mass 3. It is a very low-level, negative beta particle emitter (< 0.02 m.e.v.) w ith a half life of about twelve years. The lability of the isotope in the C— 1 bond is less than in the C—D bond, w hich in turn is less than in the C- -H bond. ... 

As a result of this recycling is replaced by non-radioactive hydrogen, consequently the ratio... 

Jenkins WA, Yost DM (1959) On the kinetics of the exchange of radioactive hydrogen between hypophosphorous acid and water. The mechanism of the oxidation of hypophosphorous acid. J. Inorg Nucl Chem 11 297-308... 

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