Neutron activation analysis of organohalogens in Chinese human hair

To effectively extract organohalogens from human hair, two factors, the extracting time and hair length on the extraction efficiency of organohalogens were studied by neutron activation analysis (NAA) and gas chromatograph-electron capture detector (GC-ECD), respectively. Furthermore, the concentrations of extractable organohalogens (EOX) and extractable persistent organohalogens (EPOX) in hair samples from angioma and control babies were also measured by the established method. The results indicated that the optimal Soxhlet-extraction time for EOX and EPOX in hair was from 8 to 11 hours, and the extraction efficiencies for organochlorine pesticides in hair were in the order of powder >2 mm>5 mm. Also, the mean levels of EOC1 and EPOC1 in hair of the angioma babies were significantly higher than those in the control babies (P _EOC1<0.01; P _EPOC1<0.05), which implied the possible relationship between the environmental pollution and angioma.     

Neutron activation analysis of hair failure of a mission

The presence and the concentration of trace elements in hair are subject to variations according to a number of factors. The primary investigations consist in a statistical interpretation of (1) the distribution of the oligo-elements in a homogeneous hair sample, (2) the distribution over one particular head, (3) the evolution in samples taken at successive intervals, (4) the distribution over a population. Our study was mainly concerned in the influence of the time factor, and revealed an unpredictable behaviour of the elements under investigation (As, Sb, Au, Mn, Hg, Cu). There was only one exception: Zn. This unpredictable behaviour of most of the oligo-elements is due to their being influenced by such external conditions as environment, washing, hair dyes, diet and drug intake. The identification of hair samples on the basis of concentrations so inconstant and easily influenced, is a most impromising endeavour. Furthermore the irregularity in distribution of the oligo-elements over the head of one and the same person is not of a nature to make things easier. The existence of these factors not only wellnigh excludes the possibility of an identification, but they furthermore make it difficult to confirm unequivocally that a hair specimen belongs to a given person, to the exclusion of any other.     

Neutron activation analysis of human hair for environmental purposes

The possibility of using human hair as a monitor for the pollution of the environment with metals is discussed. Analyzed are 15 cases by means of Instrumental Neutron Activation Analysis. Elements Se, Cu, Ca, Na, Mn and S in Bulgarian hair are compared with those from other countries. Analyzed cases are divided into two groups: metal burdened and nonburdened. A difference in Na, Ca and Mn content in hair of both groups is observed. A value of Mn is outlined which indicates with a high probability the metal burden of a person.     

Neutron activation analysis of mercury contents in head hair of dentists in Japan

Mercury contents in head hair of 58 dentists employed at the NUSD hospital and 50 dentists employed at the private hospitals or clinics were determined using neutron activation analysis. The arithmetic means were 5.8 ppm and 5.2 ppm, and geometric means were 5.4 ppm and 4.8 ppm, respectively. They were much lower than the values reported in the past year, and agreed well with those of normal Japanese men of the same age. Therefore, it was concluded that the mercury pollution in the working environment of dentists might be practically non-existent in Japan today.     

Neutron activation analysis challenges: Problems and applications in biomedical and other areas

Developments in neutron activation analysis in its various modes for trace element determination are described with reference to reactor and other neutron sources, competing methods, tomography and detection systems. A selected number of areas of application are highlighted which provide challenges into the next millennium and to which a useful and in some cases a unique contribution can be made. The role that neutron activation analysis can play in decommissioning, landmine detection, boron neutron capture therapy, Alzheimer's disease, diabetes mellitus, the complex mechanisms of initiation and termination of feeding and obesity as well as in scar formation and the requirements for artificial skin are presented.     

Neutron activation analysis of trace metals in the hair and organs of small animals treated chronically with Hg and Mn

For the purpose of studying the secretion of exogenous toxic metals into hair, relation between their concentrations in hair and those in organs, and the metal shift, Hg or Mn was orally administered to guinea pigs for protracted periods, the distributions of metals in hair and organs were examined by means of neutron activation analysis. It was found that the administration of Hg at high dose resulted in abnormally high Hg levels in hair from the 2nd dosing week and in organs after 25 week dosing, and in a reduced motor activity after 25 week administration. There occurred metal shifts in hair as well. Administration of Mn at high doses, on the other hand, showed no such biological influences, although a dose-dependent increase of Mn in hair was detected with time.     

Neutron activation analysis of indium

The extraction and extraction-chromatographic behavior of many elements in the tributylphosphate — HBr solution system has been studied. The investigation performed has made it possible to develop a simple technique for neutron activation determination of 22 impurity elements in high purity indium samples with detection limits from 0.1 ppm for Fe and Zr to 0.01 ppb for Na, Sc, Cu, As, La and W.     

Neutron activation analysis of radiopharmaceuticals

In order to understand the chemical form of soluble technetium in paddy soil and its availability to a rice plant, soil incubation and uptake experiments have been carried out using^95mTc as a tracer. The chemical form of the soluble Tc was observed by gel chromatography and found not to be pertechnetate, but rather to be associated with soluble organic matter. An uptake experiment with rice seedlings using nutrient solution showed that this Tc-organic matter complex was less available than pertechnetate.     

Neutron activation analysis of scandium

A neutron activation method is proposed for the determination of trace quantities of scandium, down to submicrogram level, in rocks, ores and meteorites. The sample and standard are irradiated intermittently for a total of 30 h, at a neutron flux of 5·10¹¹ n/cm²/sec; the radiochemical separation consists essentially of a one-step anion exchange. The induced γ-activity of ⁴⁰Sc, 85 days, isolated from the sample is measured and compared with that of a standard. The chemical yield averages 85% and there is a considerable saving of time in the radiochemical work. Results are quoted for the scandium contents of 2 standard rocks, cassiterite and several stony meteorites. Details of conflicting nuclear reactions are also given.     

Neutron activation analysis of soils

Résumé On décrit l'analyse de sols par activation neutronique au moyen de détecteur Ge(Li) à haute résolution pour la recherche de 31 éléments. Les éléments déterminés comprennent des métaux alcalins, des terres rares et des éléments de transition, la plupart d'entre eux sont utilisés, comme indices de différenciation géochimique et d'autres sont utilisés en tant que facteur de nutrition dans la physiologie des plantes. Quelques éléments comprenant Na, K, Rb, Cs, Ba, La, Ce, Sm, Eu, Th, Zr, Hf, Ta, Mn, Co, Fe, Sc, Cr, Sb, Ca, V, Al, Ti, Br et U ont été déterminés par spectrométrie gamma non-destructive, et d'autres Mo, W, Sr, Cu, Zn et Ga après une simple séparation radio chimique basée sur un échange d'ions et une extraction par solvant. On a employé l'activation dans les neutrons épithermique pour la recherche de l'U, utilisant des neutrons de réacteur. Les risques d'interférence dans les réactions et dans les spectres gamma, l'autoabsorption et les autres causes possibles d'erreur sont analysées et évaluées quand c'est possible. Les résultats sont donnés en temps que moyenne de plusieurs dosages. Dans tous les cas, on est parvenu à une grande précision.      

Neutron activation analysis of iodine in soil

A simple pre-irradiation procedure for the separation of iodine from soil has been developed. A soil sample was heated in a quartz tube for 15 min at about 900 °C. The evaporated iodine was collected in activated charcoal, which was produced from phenol resin with low impurities. The charcoal, with sorbed iodine, was irradiated by neutrons and the¹²⁸I produced was measured. A successful elimination of the background radioactivity due to the matrix elements was possible with this separation procedure. The detection limit by this method for soil samples was about 0.1 mg/kg (dry). The method has been applied to analyze selected soil samples.     

Neutron activation analysis of rhenium in rocks

A method for neutron activation determination of rhenium in rocks has been developed. Fusion with potassium hydroxide containing 15% water in a Teflon beaker was used in decomposition of irradiated samples. The purification procedure is given. Rhenium in the rocks is in the range of 1-10 ng/g.     

Neutron activation analysis of water and waste

The neutron activation method has been applied to the determination of Ag, Cd, Co, Cr, Cu, Fe, Hg, Mo, Se and Zn in waters and wastes. The method involves decomposition of organic substances by ozonation, preconcentration of elements to be determined by coprecipitation with thionalide at pH 9 or sorption on Dowes 1×2 loaded with 8-hydroxyquinoline-5-sulfonic acid at pH 7, irradiation of the concentrate, radiochemical separation of the respective radioisotopes and gamma spectrometric measurement of the activity. Accuracy and precision of the determination have been evaluated.     

Neutron activation analysis of semiconductor silicon

The determination of impurities in semiconductor silicon by nondestructive and destructive NAA is described. To improve the detection limit, a multiple beta—single gamma detector assembly is used. It is shown that²⁴Na is also produced from silicon by a (n, αp) reaction with reactor neutrons. The cross-section with fission neutrons is 1.8·10⁻⁹ barn.     

Neutron activation analysis of lithium niobate

A radiochemical neutron activation analysis procedure for the determination of Ta, W, Ir, Pt, Au, Cu, Cr, Co and Zn in lithium niobate has been developed. The method involves a one-step removal of radioactive nuclides of Nb, Ta and W representing the dominating radioactivity of the irradiated sample. After irradiation, the sample is fused with inactive carriers and Na₂O₂ in a nickel crucible. The fused cake is dissolved in HCl–H₂O₂ and Nb, Ta and W are homogeneously precipitated. The impurities are separated by combinations of precipitation and ion-exchange separations for precise -ray measurements with an overall chemical yield of 70% to 90%. The results are discussed.     

Neutron activation analysis of urinary stones

Human vesical, urethral and renal stones were analyzed for the trace elements Co, Cu, Mn, Zn and Mo. Statistical correlations between the elements determined were sought which would be of possible interest in further research on the initial causes of urinary stone formation in the human body. This research project was funded by a grant from the National Research Council of the Philippines. Read at the 40th Annual Convention of the Philippine Medical Association held in Manila, May 9, 1947.     

Neutron activation analysis of Cuban soils

Thirty elements were determined by INAA in Cuban soil samples collected in 17 zones from western regions of Cuba, which were affected by neuropathy epidemic in 1992. The presence of toxic elements was evaluated to provide data for the analysis of possible paths of intoxication through local agriculture product consumption. The results obtained for As, Th and U are compared with similar data reported on literature.     

Neutron activation analysis of Bawachi seeds

Seeds of (the plant) P. Corylifolia Linn (Bawachi) known for their therepeutic value in indigenous medicine have been analysed for Cu, As, Sb and Se by thermal neutron activation analysis involving substoichiometric extraction and precipitation technique. The amounts of Cu, As, Sb and Se per gram of seeds dried at 80°C are 16.0±1.1 μg, 0.90±0.4 μg, 12.1±0.6 μg and 4.0±0.2 μg respectively.