Bromine neutron activation

Gladney and Perrin [11] used epithermal neutron activation analyses to determine down to 50ppm total bromine in soils. Excellent agreement with recommended values were obtained for a range of Canadian reference soils (Table 12.4). 

Randle and Hartman [12] used thermal neutron activation in analysis to investigate total bromine in humic compounds in soil. Bromine was extracted from the soil water with sodium hydroxide or sodium pyrophosphate, then the extract dried prior to analysis. 

Potassium bromate is a widely used dough conditioner. However, if it is used in excessive quantities in bread products then appreciable residues (> 1 mg/kg) can remain which is of concern since it is a cancer suspect agent. Its routine analysis is laborious, time-consuming and difficult by HPLC, and Cunningham and Warner (2000) described the development of an instrumental neutron activation method for determination of bromine while HPLC was used to determine bromate in selected samples. 

Our results indicate that x-ray fluorescence is highly useful for rapid and reasonably accurate analyses of whole coal for trace elements. Because of the speed and simplicity of the method, it is highly adaptable to large-scale surveys of coal resources. A suite of 24 samples can be analyzed for 21 elements in 3 days by manual instrumentation. While this simple procedure can not be used to determine certain elements, the time-saving factor over other methods (40 or 50 to 1 in the case of bromine by neutron activation) without loss of accuracy may well make x-ray fluorescence the method of choice for many elements. Improved equipment, such as nondispersive systems and automation, could extend the application of x-ray analysis to a dominant position for determining trace elements in whole coal. 

Bromine-82 has a half-life of about 36 hours this is not sufficient for the isotope to be used conveniently in tracer work especially if labelled reagents have first to be prepared and purified. Low concentrations of bromine in small specimens of organic materials, such as polymers, can be determined by the method of neutron activation analysis (2). The various substances are prepared using ordinary bromine and then samples are bombarded with thermal neutrons so that the nuclear reaction 81Br(n, y)82Br occurs. Activity is therefore induced in the samples comparison with standards treated similarly permits determination of the bromine contents of the unknowns. For this technique to be applicable, it is necessary to have access to a powerful source of thermal neutrons. Neutron activation analysis can be used for the determination of very low concentrations of many elements and its general features have been fully discussed (3). 

Troth (32) has studied the polymerization of vinyl acetate in the presence of triphenylmethane and observed the effects discussed above. In practice, there are complications resulting from reactions involving the initiator radicals and the transfer agent. These complications were found also when carbon tetrabromide was used as a transfer agent in the polymerization of styrene in this case, the bromine contents of the polymers were determined by neutron activation analysis (17). 

Gladney and Perrin [6] used epithermal neutron activation analysis to determine down to 50 ppb bromine in the US Geological Survey Reference Soils GXR-2, GXR-5 and GXR-6, and the Canadian Certified Reference Soils SO-1, SO-2, SG-3 and SO-4. The values reported in Table 6.1 indicate that good agreement was obtained between neutron activation analysis results and recommended values. The relative standard deviation was on the order of 10% over the concentration range 1-15 ppm bromine ... 

Wyttenbach, A., H, R. Von-Gunten, and W. Schcrle Determination of Bromine Content and Isotopic Composition of Bromine in Stony Meteorites by Neutron Activation. Geochim. Cosmochim. Acta 29, 467 (1965). 

Gether, J., G. Lunde, and E. Steinnes. 1979. Determination of the total amount of organically bound chlorine, bromine and iodine in environmental samples by instrumental neutron activation analysis. Anal. Chim. Acta 108 137-147. 

A reasonably complete analysis of the inorganic chemical composition of the aerosol requires much effort and involves, in addition to wet chemical methods, instrumental techniques such as neutron activation analysis, atomic absorption spectroscopy, or proton-induced X-ray emission (PIXE). These latter techniques yield the elemental composition. They furnish no direct information on the chemical compounds involved, although auxiliary data from mineralogy, chemical equilibria, etc. usually leave little doubt about the chemical form in which the elements occur. Thus, sulfur is present predominantly as sulfate, and chlorine and bromine as Cl- and Br-, respectively, whereas sodium potassium, magnesium, and calcium show up as... 

Arsenic levels below 10 ng/g can be readily detected in petroleum by instrumental neutron activation analysis. The most convenient technique involves direct gamma counting based on the 75As (n, y) 76As reaction with a principle radiation of 559 keV. After a 1-hr irradiation at a neutron flux of 1012 n cm"2 sec-1, the arsenic may be counted in a relatively short time. The method requires a high resolution Ge(Li) detector to avoid interference from bromine (550 keV) or antimony (564 keV). 

Abedinzadeh, Z. and I. Bayat Determination of bromine residues in Iranian tobacco by neutron activation analysis ... 

Cornells, R.. Lemey, G., Mees, L. and Versieck, J. Measurement of bromine in human blood serum by neutron activation analysis. Unpublished results. 

Using the method of short-term instrumental neutron activation analysis (INAA) (Vobecky et ai, 2000), we simultaneously determined the concentration of bromine, chlorine and sodium in the samples of mother s milk taken... 

Hou, X., Chai, C. Qian, Q. (1997). Determination Of Bromine And Iodine In Biological And Environmental Materials Using Epithermal Neutron Activation Analysis. Fresenius Anal Chem, Vol.357, pp 1106-1110, ISSN 1432-1130... 

Manganese, bromine, cobalt, vanadium, arsenic, antimony, copper, selenium, aluminum, and lanthanum Tubers Neutron activation analysis... 

Elson, C.M., Ackman, R.G. and Chatt, A. (1983) Determination of selenium, arsenic, iodine and bromine in fish, plant and mammalian oils by cyclic instrumental neutron activation analysis. J. Am. Oil Chem. Soc. 60, 829-832. 

R.J. Norstrom, A.P. Gilman and D.J. Hallet, Total organically-bound chlorine and bromine in Lake Ontario Herring Gull eggs, 1977, by instrumental neutron activation and chromatographic methods, Sci. Total Environ. 20 217 (1981). 

It was proved that total chlorine, bromine, and iodine content of water samples can be determined with neutron activation analysis however, the high cost and less number of instruments available hinder the broad-scale application of that very sensitive technique in everyday water analysis [80-82]. 

Zn, Cd, Hg, Cu, As, and Se in the individual elution fractions by RNAA. Because of high levels of sodium and bromine, the background in the gamma spectrum in tissue samples are generally high after neutron activation and where many trace elements of interest are present in quite low concentration, displaying only very small peaks. RNAA is an ideal solution to this problem. 

Neutron activation analysis (NAA) has been used for many years with stationary equipment for identification and determination of chemical elements. Of present interest is its use to determine the three characteristic elements chlorine, arsenic and bromine, which appear in arsenicals and some blister agents. Efforts are under way now to develop mobile equipment. 

Bthyl bromide Is Irradiated with thermal neutrons and the active bromine la separated ea HBr by Sallord-Chelmera process. Hen, by saturating with tetro-butyl alcohol to the HBr, tetrabutyl bronlde (3 g) le synthesised. The tetrabutyl hramide Is dissolved In 200 nl of aqueous alcohol (73 1 ). Tha radioactive... 

The lighter homologue of iodine in the Periodic System of the Elements, namely bromine, is also produced by nuclear fission. Due to the comparatively low fission yields of the relevant bromine isotopes and their short halflives, they are only present in the primary coolant in very low activity concentrations and are of no significance in practice. The only bromine isotope that should be mentioned here, Br, is a neutron emitter quite similar to the heavy fission product iodine isotopes. 

There is a limit to the negative period that can be developed in a reactor by negative reactivity additions. Soon after the insertion of a large amount of negative reactivity such as a scram, the prompt neutron population decreases to a low level. Neutron population is predominantly the result of delayed neutrons which are produced by fission product decay. Within a short time, 2-3 minutes, all of the short lived delayed neutron precursors have decayed away. At this point, and from this point on, the core neutron population is sustained by decay of the longest lived fission product precursor, bromine-87, with a half life of = 55.72 seconds. Since the rate at which core neutron population decreases is determined by radioactive decay of bromine-87, an effective reactor period can be calculated by setting equations (2,9) and (4.7) equal. Neutron population, N will be used to replace activity, A, and power, P, respectively in the two equations. 

The principal components of the stored activity for an 1100-MWe PWR are given in Table 12.7, which is taken from the APS study. The top line applies to the reactor immediately after shutdown following a long period of operation at full power, while the remainder of the table illustrates the rate of decay of activity, as a function of time after shutdown. The activities of the iodine and bromine isotopes, and the noble gases, whose behavior is particularly important in the event of a major dispersal event, are shown separately, and the activity induced by neutron irradiation of the reactor structure and coolant is also listed. The absorption of jS particles and y rays in the fuel and cladding leads to a considerable generation of heat in the core the last column of the table gives the total thermal power produced in this way as a function of time after shutdown. 

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