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1.
M. Ebihara H. Ozaki F. Kato H. Nakahara 《Journal of Radioanalytical and Nuclear Chemistry》1997,216(1):107-112
Chlorine, bromine and iodine (hereafter, halogens) were detemined for rock samples by radiochemical neutron activation analysis. The powdered samples and reference standards prepared from chemical reagents were simultaneously irradiated for 10 to 30 minutes with or without a cadmium filter in a TRIGA-II reactor at the Institute for Atomic Energy, Rikkyo University. The samples were subjected to radiochemical procedures of halogens immediately after the irradiation. Iodine was firstly precipitated as PdI2, and chlorine and bromine were successively precipitated as Ag-halides at the same time. In this study, geological standard rocks, sedimentary rocks and meteorites were analyzed for trace halogens. In some Antarctic meteorites, iodine contents were observed to be anomalously high. Chlorine contents also are somewhat high. The overabundance of iodine and chlorine must be caused by terrestrial contamination on the Antarctica. 相似文献
2.
Determination of bromine and iodine in biological and environmental materials using epithermal neutron activation analysis 总被引:1,自引:0,他引:1
Xiaolin Hou Chifang Chai Qinfang Qian Chunsheng Li Ke Wang 《Analytical and bioanalytical chemistry》1997,357(8):1106-1110
Epithermal neutron activation analysis (ENAA) was applied to the determination of the contents of bromine and iodine in 40
biological and environmental standard reference materials and Chinese diets. Boron nitride (BN) for solid samples and BN+Cd
for liquid samples were adopted as shield material. Irradiation was carried out in inner and outer irradiation sites in a
Miniature Source Reactor (MNSR) for solid and liquid samples, respectively. The 443 keV photopeak of 128I and the 616 keV photopeak of 80Br were used. The precision of measurement (relative standard deviation) is 2∼6% for contents of iodine of more than 100 ng/g
and 8∼12% in the 20∼100 ng/g range in solid samples, and 12∼18% at less than 100 ng/ml in liquid samples. For bromine, the
precision of measurement is 2–8% for solid samples and lower than 13% for liquid samples. The detection limits under experimental
conditions varied between 10∼30 ng/g, 55∼95 ng/g and 25∼68 ng/g for iodine and 50∼150 ng/g, 200∼450 ng/g and 100∼300 ng/g
for bromine in ENAA with BN shield in inner irradiation sites, with Cd shield and BN+Cd shield in outer irradiation sites,
respectively.
Received: 13 June 1996 / Revised: 2 September 1996 / Accepted: 19 September 1996 相似文献
3.
The determination of chlorine, bromine and iodine present as non-polar, hydrophobic hydrocarbons in environmental samples is reported. The organohalogen compounds are separated from water into an organic phase by on-site liquid—liquid extraction, and from biological material by procedures based on lipid phase extraction and codistillation. After removal of inorganic halides by washing with water and concentration of the sample by evaporation of the solvent, the resulting extracts are analyzed for their chlorine, bromine and iodine contents by instrumental neutron activation analysis. Strict attention is paid to the possibility of contamination in every step of the procedure. Background values in routine analysis are approximately 100–200 ng of chlorine, <5 ng of bromine and <3 ng of iodine. 相似文献
4.
The determination of Zn in geological samples using instrumental neutron activation analysis is usually done using the 64Zn(n,γ)65Zn reaction and its 244 day half-life. However this analysis has proven to be potentially difficult. This is due to its relatively low neutron absorption cross section and gamma ray intensity, and the relatively high neutron absorption cross section and gamma intensity of 46Sc, which has an energy peak that is only 5 keV greater than 65Zn. The use of a high resolution detector makes it possible to differentiate between the 65Zn and 46Sc photopeaks peaks. However, the dominating 46Sc gamma ray can even make peak fitting routines unsuccessful in the proper determination of 65Zn. The use of a Compton suppression system suppresses the 46Sc peak, which has two coincident gamma-rays, and this greatly improves the ratio of the height of the 46Sc 1120.5 keV photopeak to the 65Zn 1115.4 keV photopeak. Irradiating the sample with epithermal neutrons also improves the measurement since 65Zn has a higher cross section for epithermal neutrons rather than thermal neutrons, whereas 46Sc has a higher thermal cross section. Another technique to determine zinc is the use of 68Zn(n,γ)69mZn reaction with its 13 h half-life using epithermal neutrons and Compton suppression INAA. However, the 438 keV gamma ray of 69mZn has no interference with any adjoining photopeak. A critical comparison of these two methods is given. 相似文献
5.
S. Landsberger A. Massicotte J. Braisted S. Gong 《Journal of Radioanalytical and Nuclear Chemistry》2008,276(1):193-197
Arctic pollution is a problem of great concern, because its characteristics (transportation, assimilation into the environment,
etc.) are complex and not fully understood. Detection of elemental constituents has been undertaken through the use of neutron
activation analysis and Compton suppression (to lower the detection limits for radionuclides characteristic of mainly single
gamma-ray emission) to discover possible pollutant sources. The goal of this project was to perform a feasibility study to
determine the suitability of neutron activation analysis (NAA) to evaluate cadmium concentrations on air filters collected
in the Arctic. 相似文献
6.
Ch. Yonezawa H. Matsue M. Yukawa 《Journal of Radioanalytical and Nuclear Chemistry》2003,255(1):105-109
In order to investigate the ingestion of iodine by human body and to know its content in organs, instrumental epithermal neutron activation analysis was used in conjunction with Compton suppression gamma-ray spectrometry by measuring the 128I short-lived nuclide. The interferences of 24Na and 38Cl induced from NaCl in a sample were reduced by factors of about 6 and 15 to 41 by employing the epithermal neutron activation and Compton suppression gamma-ray spectrometry, respectively. The present method can be used to determine iodine at levels higher than 11 ppb. It was applied to the determination of iodine of more than 35 ppb in various biological reference materials. 相似文献
7.
S. Landsberger 《Journal of Radioanalytical and Nuclear Chemistry》1994,179(1):67-79
An overview of Compton suppression neutron activation analysis (NAA) is given. The basic theory of the technique, its experimental design, uniqueness, and limitations are discussed. Experimental data showing its usefulness for the low level determination of several key elements in environmental samples that can not be obtained using conventional non-destructive neutron activation is deliberated. 相似文献
8.
Despite the role of iodine for proper development of the brain and the functions of the element, the accurate data on its concentration in brain tissue are largely lacking, the main reason being analytical difficulties associated with determination of the element especially at low levels. In this work, samples from human brain regions from Hungarian patients were analyzed using epithermal and radiochemical neutron activation analysis (ENAA and RNAA, respectively). The RNAA procedure is based on alkaline-oxidative fusion followed by extraction of elemental iodine in chloroform. The results were checked by the analysis of biological standard reference materials, namely bovine liver, bone meal and diet, and by comparison with previous results obtained by a different RNAA procedure. 相似文献
9.
J. Kučera G. V. Iyengar Z. Řanda R. M. Parr 《Journal of Radioanalytical and Nuclear Chemistry》2004,259(3):505-509
Samples of diets from China, Japan, Korea, India, Pakistan and Philippines were analyzed using epithermal and radiochemical
neutron activation analysis (ENAA and RNAA, respectively) within the framework of the IAEA project “Reference Asian Man”.
The RNAA procedure was based on alkaline-oxidative fusion followed by extraction of elemental iodine in chloroform. The analytical
methods employed are discussed in terms of detection limits and uncertainties of the results obtained. For quality control
purposes a number of NIST biological reference materials, namely diets and foods were analyzed. Results for the diet samples
indicate that achieving the WHO recommended daily allowance for iodine may be a problem in most of the above given countries.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
10.
V. L. Spate J. S. Morris S. Chickos C. K. Baskett M. M. Mason T. P. Cheng C. L. Reams C. West C. Furnee W. Willett P. Horn-Ross 《Journal of Radioanalytical and Nuclear Chemistry》1995,195(1):21-30
An epithermal instrumental neutron activation analysis (EINAA) method, using a boron nitride irradiation capsule compatible with use in the University of Missouri Research Reactor pneumatic-tube irradiation facility, has been developed for the analysis of iodine in human nails. The principal objective was to determine if the nail could be used as a means of monitoring dietary intake of iodine. The EINAA method was used to analyze nails from subjects having iodine intakes that could be qualitatively differentiated. Iodine concentrations in nails from these subjects were positively correlated with apparent iodine intake. 相似文献
11.
Y. Serfor-Armah B. J. B. Nyarko J. Holzbecher E. H. K. Akaho E. K. Osae A. Chatt 《Journal of Radioanalytical and Nuclear Chemistry》2003,256(2):259-262
Epithermal instrumental neutron activation analysis (EINAA) together with Compton suppression system were optimized and used to analyze several food samples for the determination of low levels of iodine. The method involved the irradiation of samples in the outer epi-cadmium site of the Dalhousie University Slowpoke-2 reactor facility. The samples were then counted directly without any chemical treatment on an anticoincidence counting system. This system comprised a 25 cm3 hyperpure Ge detector, a guard detector consisting of a 10"×10" NaI(Tl) annulus with five photomultiplier tubes (PMTs) and a 3"×3" NaI(Tl) plug with one PMT. Iodine was quantitatively analyzed using the 443 keV photopeak of 128I. The precision and accuracy of the method were evaluated using real samples and biological reference materials, respectively. The precision of the method was calculated as percent relative standard deviation and in all cases was within ±5%. The agreement between our iodine values and those of the certified values was generally within ±10%, suggesting an excellent accuracy of the method. The detection limits of the various samples calculated, with the lowest value of 20 ppb. The values of iodine determined ranged between 24 to 3080 ppb. The methods and results are presented. 相似文献
12.
J. B. Luten H. A. Das C. L. De Ligny 《Journal of Radioanalytical and Nuclear Chemistry》1977,35(1):147-155
A routine-method for the determination of bromine and iodine in environmental water by neutron activation is presented. The
elements are isolated by isotope exchange between the irradiated sample and a solution of Br2 or I2 CCl4. The method is not sensitive to the chemical species in which the halogen is present. The lower limit of the determination
is 1.0 μg Br·1−1 and 0.1 μgI·1−1. 相似文献
13.
W. B. Stroube Jr. W. C. Cunningham G. J. Lutz 《Journal of Radioanalytical and Nuclear Chemistry》1987,112(2):341-346
Epithermal-neutron activation analysis (ENAA) was applied to the analysis of foods for iodine. The procedure involves irradiation of wet foods in a boron nitride, vessel, followed by direct counting of the 442.9 keV gamma ray of128I without any processing of the sample. Three research reactors were evaluated for use in determining iodine by ENAA. The University of Virginia reactor at Charlottesville was chosen for this study because the reactor facilities minimized thermal heating of the boron nitride vessel, enabling irradiation of larger, more representative analytical portions. Iodine concentrations ranging from <0.003 to 0.74 g/g are reported for 17 different food matrices. 相似文献
14.
Iodine abundances in NBS biological SRMs and various organs of rats were evaluated by epithermal neutron activation analysis with a boron carbide filter. Detectability of iodine in different biological materials by this method is discussed.
相似文献15.
Determination of iodine in milk products and biological standard reference materials by epithermal neutron activation analysis 总被引:1,自引:0,他引:1
The biologically essential trace element, iodine, has been determined in various milk products by epithermal neutron activation analysis /ENAA/ after sealing in quartz and irradiating under cadmium cover. The method was extended to several IAEA and NBS biological reference materials. 相似文献
16.
D. Chultem Dz. Ganzorig T. Gun-Aajav 《Journal of Radioanalytical and Nuclear Chemistry》1979,50(1-2):195-204
A method of iodine determination in biological samples by means of resonance neutron activation is described. This method
has made it possible to determine the iodine content of such samples as children's thyroid gland, grass frog's skin, etc. 相似文献
17.
E. S. Gladney W. A. Sedlacek W. W. Berg 《Journal of Radioanalytical and Nuclear Chemistry》1983,78(1):213-225
A comparative determination of bromine and iodine in three distinct air sampling media by instrumental thermal and epithermal neturon activation analysis is presented. Open ocean air samples from the mid-Atlantic region were collected on ultra-pure nylon, Nuclepore, and activated charcoal substrates. The bromine and iodine content of each substrate was determined by both epithermal and thermal activation techniques. Good agreement was found within most thermal-epithermal pairs. Relative to the thermal activation procedure, the epithermal technique yields peak/background ratio improvements ranging from a factor of 1.30 to 9.5. Nylon substrates showed the smallest improvement at 1.30 and both Nuclepore and activated charcoal substrates showed improvement factors of 6.7 and 9.5 for bromine and iodine respectively. 相似文献
18.
A radiochemical procedure for simultaneous determination of lead (203Pb), thallium (202TI) and cadmium (115Cd115mIn) after fast neutron activation, based on ion-exchange separation from bromide medium and additional purification steps for Pb and Tl is described. Radioactive tracers210Pb and109Cd were used for determination of the chemical yields of Pb and Cd; for Tl it was determined gravimetrically. Two standard reference materials, BCR CRM No. 146 Sewage Sludge and NIST SRM 1633a Coal Fly Ash were analyzed and satisfactory agreement with certified values was obtained. 相似文献
19.
Conclusions In this work a review of the development of compton suppression is presented. It was shown that the application of Compton-suppression counting in instrumental NAA reduces the detection limits and improves the accuracy for a list of elements by substantial reduction of the background of the -spectroscopy. Results for certified reference materials obtained through the use of Compton suppression are normally more accurate and in agreement with the published values. Compton suppression is particularly helpful for low level concentrations in environmental samples to those elements which exhibit severe special interferences in the normal NAA counting. A list of the elements with isotopes having single or close to single -ray decay schemes and which could benefit from Compton-suppression counting is presented. Also, evaluation is made regarding the reliability of Compton suppression with increase in the overall dead-time of the counting. It was concluded that this method does not provide accurate quantification of the isotopes when the overall dead-time exceeds the 10% range. Investigation of the natural background was performed with Compton suppression for the purpose of neutron activation analysis application. The method presented proves to broaden the application of NAA and helps in its competition for simplicity, accuracy and reliability with the modern methods of elemental analysis. Future application of coincidence spectrometry in activation analysis should include better enclosing of the primary detector, utiliza5tion of x-ray and well type detectors, -, -, and -- coincidence techniques. 相似文献
20.
S. :andsberger 《Journal of Radioanalytical and Nuclear Chemistry》1992,161(1):5-10
Instrumental epithermal neutron activation analysis in conjunction with Compton suppression methods has been used to determine cadmium concentrations in seven biological reference materials. The114Cd(n, )115CD(t1/2=53.3h115mIn(t1/2=4.5h) reaction using the 336.3 keV photopeak was successfully employed to achieve an overall precision between 4%–15% and detection limits between 10–20 ng/g. The accuracy of the results as compared to the certified or compilation values was in excellent agreement. 相似文献