As radiolytic products

Alkanes, as radiolytic products 907 Alkanesulphinates as radiolytic products 907 in stereospecific synthesis of sulphoxides 298, 299... 

Sulphones (coni.) allenic - see Allenic sulphones allyl - see Allyl sulphones aryl unsaturated alkyl - see Aryl unsaturated alkyl sulphones aryl vinyl - see Aryl vinyl sulphones as radiolytic products 907 bicyclic - see Bicyclic sulphones bis(/ -hydroxyalkyl) - see Bis... 

In some cases, the identity of paramagnetic "satellite ions" was established by ODMR [42,44,48]. For example, 9,10-octalin + was identified in decalins and their solutions [42]. ODMR spectra of "satellite ions" in cyclohexane were related to EPR spectra of matrix-isolated cyclohexene + (Note that in the liquid cyclohexane, cyclohexene + undergoes a fast ring-puckering motion that averages hyperfine coupling constants for equatorial and axial protons, so the the EPR spectra of cyclohexene + in liquid and solid matrices are different) [42,44,48]. In both of these cases, the olefin radical cations were formed in spurs rather than in a reaction of the solvent hole with the olefin in the solvent bulk [42] (octalins gradually accumulate as radiolytic products). Olefin "satellite ions" were also observed in squalane [24]. 

The product yield should be independent of temperature and insensitive to variation of experimental conditions during the course of radiolysis such as accumulation of radiolytic products, change in pH and so forth. 

Understandably, most workers who use radiolysis, photoionization, CTFS, or CTTS as the means for generation of (secondary) radical ions pay little attention to the nature of short-lived precursors of these ions. After all, the subject of interest is a secondary rather than a primary ion. This ad hoc approach is justifiable because radiolytic production is just another means of obtaining a sufficient yield of the radical ion. Quite often in such studies, the radiolysis is complemented by other techniques for radical ion generation, such as plasma oxidation, electron bombardment-matrix deposition, and chemical and electrochemical reduction or oxidation. While the data obtained in these studies are useful, there is little radiation chemistry in such—nominally, radiation chemistry—studies. 

Chemical and biological effects of ionizing radiation are thought to occur through two main mechanisms direct interaction of the radiation with food components and living cells in materials exposed to it, and indirect action from radiolytic products, such as the radicals formed from water molecules (see Chap. 12). 

The effect of the electron scavenger, CS2, is explained as due to preventing the neutralization of the cations in the system and subsequent reaction of in the state with cyclopropane or with the radiolytic products of the substrate. In the presence of CS2 the major product is methyl iodide similarly to the major product of Br found by De Jong and coworkers . However the analog to the main product in the case of I2 or O2 as scavenger, namely, n-propyl bromide was not found at all by De Jong and co workers. They found the second and third major products to be allyl bromide and cyclopropyl bromide while Certout and Schleifer did not find the respective iodides at all. It is not clear if this is due to the difference between Br and I or due to the different amount of radiolysis induced by each of them. 

Radiolysis experiments using heavy ion beams (protons and heavier atomic nuclei stripped of all electrons) occupy an important role, despite the relatively small number of investigators in this area. Because heavy ions have much higher LET values, the pattern of energy deposition, or track structure, is much denser than with "lighter" radiations. The variation of yields of radiolytic products as a function of LET, and the effects of variable... 

Gas chromatography (GC) with an infrared (IR) detector was introduced as a method to detect volatile radiolytic products, some of which were hypothesized to be responsible for the bad smells emanating from irradiated drugs. Thiocyanic acid was held responsible, for example, for the sulfurous smell in irradiated ampicillin. The head-space (HS) injection technique for GC and the on-line MS detection allowed new approaches to detect radiosterilization [12]. Many volatile radiolytic products were identified from the mass spectral libraries. Some ofthe compounds identified such as aldehydes, esters and sulfides were quite malodorous. A few of the volatile radiolytic products came from the degradation of drug molecules by the ionizing radiation, whereas residual solvents played a key role in the formation of other volatile radiolytic products. 

In principle X-rays, as well as electron and gamma rays, can be used the main effect of gamma and X-rays is Compton scattering, i.e. ionisation of atoms giving rise to "primary electrons" these electrons, like those generated in an accelerator, lead to a number of other "secondary electrons" and ions. This cascade of secondary electrons (about 4000 to 6000 ionisations per initial secondary electron) loses energy in ionising the foodstuff molecules, with consequent production of free radicals and, thereby, of "radiolytic products" (Chapter 1). 

Radiation chemistry studies had shown that the radiolytic products of major food components are present in low quantities (a maximum of about 10 ppm at 10 kGy) and, moreover, do not depend on the food from which they were derived. Moreover, for major food components [4,5], these products had also been identified in foods subjected to other accepted types of food processing such as appertisation, or under natural auto-oxidation. This understanding is very important for considering general clearance of irradiated foods ... 

Two "chemical" protocols voted by the ECN are relative to food containing lipids the percentage of radiolytic products from lipids such as volatile hydrocarbons, aldehydes or butanones is directly linked to the chemical composition of lipids. In the case of another treatment such as heating there is no direct correlation between the different percentages. 

Irradiation can extend the shelf life of food so that it can be stored for long periods of time without refrigeration, as shown in Figure 21.18. However, people who oppose food irradiation are concerned about what are called unique radiolytic products—URPs, for short. These products result from chemical changes caused by the ionizing effects of radiation. 

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