Adsorbed tritium method

Benzodiazepines with reasonably high specific activity have been also tritium-la-belled165 using adsorbed tritium or activated tritium. These methods166,167 are fast and do not require one to synthesize the precursors. In the AcT (activated tritium) method the substrate to be labelled, spread on different catalyst supports (such as silica-alumina 980-25 containing 0.5% Ru, 1% Ni or 1% V alumina catalyst Al-3945, 1% Ni, 1% Pd or 5% Pd silica, 1% Ni and carbon, 4.6% Pd the metal catalysts were activated by heating to 600-700 °C in hydrogen or on untreated silica-alumina), has been reacted... 

After extensive effort to perfect the method, it was found that environmental water and memory effects occurred in the bomb reactors. Since the reactor had to be opened to change the zinc and add the water sample, environmental water was adsorbed in the reactor. Neither the environmental contamination nor memory effects could be removed completely by evacuating the reactor within a reasonable time. This technique is promising, but further work must be done to eliminate these problems before it can be used routinely for low level tritium analysis. 

Koretsky et al. calculated site densities for particular low index faces of six oxides and six silicate minerals and average site densities for cleavage and growth faces, and showed that these methods lead to very different results. Full documentation of depth, length of broken bond and Brown bond strengths of broken bonds for particular types of sites is presented. The ranges of TVs calculated by Koretsky et al. [7] and in their literature data collection (tritium exchange, acid-base titrations, NMR, adsorption and desorption of water at various conditions, and saturation experiments with different adsorbates in solution) for six oxides are listed in Table 5.1. 

Blaschke, G. Chromatographic resolutions of racemates. 11. Enantiomerically specific tritium-carbon-14-double labeled racemates, the basis of a new method for the determination of chromatographic resolution on optically active adsorbents, Chem. Her, 1974,107, 232-236. 

The methods (73,74) which have been widely used to investigate the mechanism of this reaction at several electrodes are determinations of (a) Tafel parameters, (b) stoichiometric numbers, (c) reaction orders, (d) variation of coverage of intermediate (adsorbed hydrogen as the electrode) with potential, and (e) hydrogen-deuterium or hyirogen-tritium separation factors. One of the main difficulties in these mechanism... 

Other methods have failed, the compound is simply exposed to tritium gas for several days at room temperature. Unless labile tritium is carefully removed, however, the amount of tritium adsorbed onto the surface of the molecule, as opposed to being incorporated in it, may be considerable. 

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