Tritiation recoil

Three types of radiation-induced procedures have been used including (a) recoil tritiation, (b) Wilzbach gas irradiation7 with its modifications, and (c) radiation synthesis.8 All these methods utilize high-energy ionizing radiation to achieve tritium incorporation. Wilzbach exchange7 is the most satisfactory of the three and has been the most widely used. Radiation synthesis is a relatively recent development of limited but valuable specificity. 

For tritiating heterocyclic compounds the recoil method has been used to label nicotinic acid (l)11-18 and also reserpine.14,15... 

Recent work indicates that free carbonium ions can be generated via P decay of tritiated alkanes (59,60,61). The time scale for )8-particle emission and the recoil range of the energetic electron ensures that the ion produced is isolated with respect to reorientation of its surroundings and any resultant solvation. Furthermore, the fact that carbocations often react with a rate approaching the collision frequency even in the liquid phase determines that the unsolvated ions indeed survive to react unaf-... 

I he damage from the recoil tracks of an individual tritium atom may have an effect on the labeled molecules it produces only in the liquid and solid phases, where there is considerable restraint on the motion of the tritiated molecules and radicals at the end of the track. These species can interact with fragments produced by radiation... 

It is interesting to see the pressure dependence of hot tritium reaction in cyclobutane C4H8. Recoil tritium attacks this molecule to give tritiated cyclobutane (substitution reaction) in an excited state, which either stabilizes by collision with a third body or decomposes into two molecules of ethylene. This is shown in the following scheme ... 

A method for preparing tritium-labelled oligosaccharides of hyaluronic acid has used the Wilzbach recoil technique the tritiated oligosaccharides are of potential use in studies of the mechanism of hyaluronidases. A four-fold helical form of hyaluronic acid has been detected using the data from fibre-... 

Treatment of hyaluronic acid with hydrazine removed some of the A -acetyl groups, which were reconstituted on reacetylation with tritiated acetic anhydride the tritiated mucopolysaccharide was used as a substrate in a semimicro assay for hyaluronidase. Tritium-labelled hyaluronic acid, labelled by the tritium-recoil technique, has been treated with j8-D-glucuronidase to yield tritiated oligosaccharides containing terminal, non-reducing 2-acetamido-2-deoxy-j3-D-glucopyranosyl residues. ... 

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