Tritium radioactive

Symbol H atomic number 1 atomic weight 1.0079 the lightest of all the chemical elements the first element in the Periodic Table Group lA (group 1) nonmetallic gaseous element occurs as H2, a diatomic molecule electron configuration Ish valences -i-l and-1 three isotopes H-1 or protium (99.9844%), H-2 or deuterium (0.0156%), H-3 or tritium (radioactive, ty, =12.4 yr., in traces... 

To perform an electrical measurement, at least some tiny current must flow through the entire circuit—even across the glass pH electrode membrane. Studies with tritium (radioactive 3H) show that H+ does not cross the glass membrane. However, NaH sluggishly crosses the membrane. The H+-sensitive membrane may be thought of as two surfaces electrically connected by Na+ transport. The membrane s resistance is typically 108 SI, so little current actually flows across it. 

The proton is the lightest nucleus, with atomic number one. Other singly charged nuclei are the deuteron and the triton, which are nearly two and three times as heavy as the proton, respectively, and are the nuclei of the hydrogen isotopes deuterium (stable) and tritium (radioactive). The difference in the nuclear masses of the isotopes accounts for a part of the hyperfine structure called the isotope shift. 

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

An ingenious experiment showed that this cyclization is not as simple as it seems. If the starting material is labelled with tritium (radioactive 3H) next to the ring, the product shows exactly 50% of the label where it is expected and 50% where it is not. 

Explain why achievement of nuclear fusion in the laboratory requires a temperature of about 100 million degrees Celsius, which is much higher than that in the interior of the sun (15 million degrees Celsius). Tritium contains one proton and two neutrons. There is no proton-proton repulsion present in the nucleus. Why, then, is tritium radioactive ... 

Tritium contains one proton and two neutrons. There is no proton-proton repulsion present in the nucleus. Why, then, is tritium radioactive ... 

As an additional approach in preparing a H-labeled anthraquinone, the radiochemical labeling of emodin (33) was undertaken (Groger et al., 1968). Reaction with 10 Ci tritium gas for 3 wk (Wilzbach conditions) (Wenzel and Schulze, 1962) yielded, after exchange of the labile tritium and intensive purification, crystalline emodin (33) with specific tritium radioactivity of 11.6 mCi/mmole. As usual with Wilzbach tritiations (Evans, 1974), the radioactivity was predominantly located on the aromatic nucleus, and the C-methyl radioactivity as determined by Kuhn-Roth oxidation amounted to only 8.5% of the overall radioactivity. 

The following reactions are carried out with HCl(aq) containing some tritium (jH) as a tracer. Would you expect any of the tritium radioactivity to appear in the NH3(g) In the H2O Explain. 

Deuterium is used as a moderator to slow down neutrons. Tritium atoms are also present but in much smaller proportions. Tritium is readily produced in nuclear reactors and is used in the production of the hydrogen (fusion) bomb. It is also used as a radioactive agent in making luminous paints, and as a tracer. 

A few natural isotopes are radioactive. Of the three isotopes of hydrogen, only that of mass 3 (tritium) i.s radioactive. Radioactive isotopes can be examined by other instrumental means than mass spectrometry, but these other means cannot see the nonradioactive isotopes and are not as versatile as a mass Spectrometer. 

OtherApphca.tlons. Many appHcations of adsorption involving radioactive compounds simply parallel similar appHcations involving the same compounds in nonradio active forms, eg, radioactive carbon-14, or deuterium- or tritium-containing versions of CO2, H2O, hydrocarbons. For example, molecular sieve 2eohtes are commonly employed for these separations, just as for the corresponding nonradio active uses. 

A D—T fusion reactor is expected to have a tritium inventory of a few kilograms. Tritium is a relatively short-Hved (12.36 year half-life) and benign (beta emitter) radioactive material, and represents a radiological ha2ard many orders of magnitude less than does the fuel inventory in a fission reactor. Clearly, however, fusion reactors must be designed to preclude the accidental release of tritium or any other volatile radioactive material. There is no need to have fissile materials present in a fusion reactor, and relatively simple inspection techniques should suffice to prevent any clandestine breeding of fissile materials, eg, for potential weapons diversion. 

There should be specific, saturable binding to the receptor, accompanied by pharmacological characteristics appropriate to the functional effects, demonstrable using a radioactive, eg, tritium or iodine-125, ligand to label the receptor. Radioligand binding assays (1,6) have become a significant means by which to identify and characterize receptors and enzymes (see Immunoassays Radioactive tracers). Isolation of the receptor or expression of the receptor in another cell, eg, an oocyte can be used to confirm the existence of a discrete entity. 

Tritium is radioactive and decays with a half-life of 12.26 yr. 

Any radioactive nucUde or isotope of an element can be used as a radioactive tracer, eg, chromium-51 [14392-02-0] cobalt-60 [10198-40-0] tin-110 [15700-33-1] and mercury-203 [13982-78-0],hut the preponderance ofuse has been for carbon-14 [14762-75-5],hydj ogen-3 [10028-17-8] (tritium), sulfur-35 [15117-53-0], phosphoms-32, and iodine-125 [14158-31 -7]. More recendy phosphoms-33 has become available and is used to replace sulfur-35 and phosphoms-32 in many appUcations. By far the greater number of radioactive tracers produced are based on carbon-14 and hydrogen-3 because carbon and hydrogen exist in a large majority of the known natural and synthetic chemical compounds. 

The radioactive isotopes available for use as precursors for radioactive tracer manufacturing include barium [ C]-carbonate [1882-53-7], tritium gas, p2p] phosphoric acid or pP]-phosphoric acid [15364-02-0], p S]-sulfuric acid [13770-01 -9], and sodium [ I]-iodide [24359-64-6]. It is from these chemical forms that the corresponding radioactive tracer chemicals are synthesized. [ C]-Carbon dioxide, [ C]-benzene, and [ C]-methyl iodide require vacuum-line handling in weU-ventilated fume hoods. Tritium gas, pH]-methyl iodide, sodium borotritide, and [ I]-iodine, which are the most difficult forms of these isotopes to contain, must be handled in specialized closed systems. Sodium p S]-sulfate and sodium [ I]-iodide must be handled similarly in closed systems to avoid the Uberation of volatile p S]-sulfur oxides and [ I]-iodine. Adequate shielding must be provided when handling P P]-phosphoric acid to minimize exposure to external radiation. 

Decay products of the principal radionuclides used in tracer technology (see Table 1) are not themselves radioactive. Therefore, the primary decomposition events of isotopes in molecules labeled with only one radionuclide / molecule result in unlabeled impurities at a rate proportional to the half-life of the isotope. Eor and H, impurities arising from the decay process are in relatively small amounts. Eor the shorter half-life isotopes the relative amounts of these impurities caused by primary decomposition are larger, but usually not problematic because they are not radioactive and do not interfere with the application of the tracer compounds. Eor multilabeled tritiated compounds the rate of accumulation of labeled impurities owing to tritium decay can be significant. This increases with the number of radioactive atoms per molecule. 

The nonquantitative detection of radioactive emission often is required for special experimental conditions. Autoradiography, which is the exposure of photographic film to radioactive emissions, is a commonly used technique for locating radiotracers on thin-layer chromatographs, electrophoresis gels, tissue mounted on sHdes, whole-body animal sHces, and specialized membranes (13). After exposure to the radiolabeled emitters, dark or black spots or bands appear as the film develops. This technique is especially useful for tritium detection but is also widely used for P, P, and 1. 

Tritium [15086-10-9] the name given to the hydrogen isotope of mass 3, has symbol or more commonly T. Its isotopic mass is 3.0160497 (1). Moletecular tritium [10028-17-8], is analogous to the other hydrogen isotopes. The tritium nucleus is energetically unstable and decays radioactively by the emission of a low-energy P particle. The half-life is relatively short (- 12 yr), and therefore tritium occurs in nature only in equiUbrium with amounts produced by cosmic rays or man-made nuclear devices. 

Nuclear Magnetic Resonance. AH three hydrogen isotopes have nuclear spins, I 7 0, and consequently can all be used in nmr spectroscopy (Table 4) (see Magnetic spin resonance). Tritium is an even more favorable nucleus for nmr than is H, which is by far the most widely used nucleus in nmr spectroscopy. The radioactivity of T and the ensuing handling problems are a deterrent to widespread use for nmr. Considerable progress has been made in the appHcations of tritium nmr (23,24). 

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