INAA of Some Fossil Samples from Romanian Sites

Instrumental neutron activation analysis was used to determine elemental contents of Elephas primigenius mammoth mandible bone and Pecten solarium shell fossils discovered in Romania during 1995–1996. In addition, calcareous sedimentary rock surrounding the shell fossil was analyzed. Concentrations of Al, As, Au, Ba, Br, Ca, Co, Cr, Cs, Fe, Hf, K, Mg, Mn, Na, Ni, Rb, Sb, Sc, Se, Sr, Th, U, V, Zn and the rare earth elements Ce, Eu, La, Lu, Nd, Sm, Tb, Yb were determined. The results are discussed and compared to the available data in the literature for similar fossils.     

INAA in Combination with Other Analytical Techniques in the Study of Urban Aerosol Sources

Concentrations of elements in fine and coarse PM10 samples collected in Ho Chi Minh City were determined by INAA for the purpose of characterising air pollution sources using multivariate receptor modeling techniques. Seven sources common to coarse and fine samples were identified. Resuspended soil dust is dominant in the coarse samples accounting for 41% of the particulate mass. In the fine samples, vehicle emissions and coal burning are most important accounting for about 20% each. Although a great number of elements were included in the input data for receptor modeling, the interpretation of emission sources was not always straightforward. Information on other source markers were needed. Therefore, a polarography method was used for quantifying lead, and recently, ion chromatography method became available for quantifying secondary sulphates, nitrates and other water soluble ions.     

A study of indoor radon in greenhouses in Mexico City, Mexico

Enclosed spaces in contact with soil, the main source of radon, like greenhouses have potentially high radon (²²²Rn) concentrations. Greenhouses are frequented by visitors and also are workplaces. The study of radon concentrations in greenhouses is, thus, a relevant concern for public health and environmental radiation authorities. For this study, the radon concentrations in 12 greenhouses in different locations within Mexico City were measured using nuclear track methodology. The detectors used for the study consisted of the well-known closed-end cup device, with CR-39 Lantrack^® as detector material. The measurements were carried out over a period of one year, divided into four three-month sub-periods. The lowest and highest annual mean radon concentrations found in individual greenhouses were 17.0 and 45.1 Bq/m³, respectively. The annual mean averaged over all 12 greenhouses was 27.3 Bq/m³. No significant seasonal variation was observed. Using the highest annual mean radon concentration found in an individual greenhouse, and an equilibrium factor of 0.4, the effective dose from ²²²Rn and its progenies was calculated to be 339.9 nSv/h. This corresponds to an annual dose rate of 679.8 μSv/y (0.057 WLM/y) for a worker spending 4 h a day, 5 days a week, 50 weeks a year, inside the greenhouse. For a visitor spending 12 h a year inside the greenhouse the annual dose is 2.469 μSv/y. The study of indoor radon concentrations in closed buildings such as greenhouses, which are both workplaces and open to visitors, is an important public health consideration.     

Radon in drinking water in Mexico City

Journal of Radioanalytical and Nuclear Chemistry - The anti-tumor cell proliferative effect of [111In] In-DOTA-nimotuzumab and [131I] I-ATE-nimotuzumab was systematically investigated. Both...     

Determination of Trace Elements in Aerosol Samples Collected on Polycarbonate Filters by Atomic Absorption Spectrometry

Abstract

The multi-element analysis of aerosol samples collected on polycarbonate filters and the wet digestion procedure in open vessel were investigated. The concentrations of Na, K, Ca, Mg and Zn were determined by flame atomic absorption spectrometry with a micro injection system while Cd, Pb, Cu, Ni and V were determined by graphite furnace atomic absorption spectrometry (AAS).

NIES N[ddot] 8 “Vehicle Exhaust Particulate” Certified Reference Material from the Japan Environment Agency was used to study the decomposition of the samples. Different treatments were applied in order to completely dissolve the aerosol samples. It was found that, from all the methods tested, attack with micro-quantities of HNO₃ and HCIO₄ in an air pressure digestion system was the best procedure for the determination of the elements by AAS.

The recommended method was appropriate for all elements and it was applied to real samples. Two nondestructive analytical techniques for the determination of Na, K, Ca, Mg, Zn and Pb have been compared with the proposed method: proton induced X-ray emission (PIXE) and neutron activation analysis (NAA). Results obtained by the application of these three techniques were similar.     

Epithermal neutron flux characterization of the Triga Mark III reactor, Salazar, Mexico, for use in INAA

The nonideality of the epithermal neutron flux distribution at a reactor site parameter () and the thermal-to-epithermal neutron ratio (f) were determined in 3 typical irradiation positions of the Triga Mark III reactor of the National Nuclear Research Institute, Salazar, Mexico, using the Cd-ratio for multimonitor and bare bi-isotopic monitor methods, respectively. This characterization is to be used in theK ₀-method of NAA, recently introduced at the Institute.     

Gamma radiation and radon levels in Mexico City dwellings

Gamma exposure rate and radon levels were measured in 75 single-family dwellings in Mexico City in order to correlate them with local environment. Radon monitoring was performed both indoors and outdoors using a continuous working level monitor for short-lived radon decay products; the gamma exposure rate was measured using CaSO₄: Dy+PTFE. The results obtained show a log-normal distribution. The mean indoor radon concentration is lower than 45 Bq/m³ and the mean indoor gamma exposure rate was 11.29 R/h.     

X-Ray fluorescence analysis of dry deposit samples in Mexico City

The American National Standard "Calibration and Use of Germanium Spectrometers for the Measurement of Gamma-Ray Emission Rates of Radionuclides" has been reissued as N42.14-1999. The performance tests in it can be used to make sure that a gamma-spectroscopy program is set up correctly. The same tests can also be used to verify the improvements made by program developers. However, sometimes the tests in this ANSI standard are not enough. To satisfy certain quality assurance requirements, it is necessary to demonstrate that the results are correct either by hand calculations or by comparing the results to known values.     

Multielement determination in Tillandsia by INAA

Instrumental neutron activation analysis was employed to measure 43 elements, including some macroconstituents, in the leaves of some species of the epiphytic genusTillandsia (Bromeliaceae). The results, confirming the oligotrophyc nature of the genus, are briefly discussed with regard to a possible role as multielemental environmental monitors.     

Precise and Sensitive Water Soluble Ion Extraction Method for Aerosol Samples Collected on Polytetrafluoroethylene Filters

Abstract

The widely used aerosol collection filters composed of polytetrafluoroethylene (Teflon) present a problem in the extraction of water soluble ions from the collection surface due to the hydrophobic nature of the Teflon. A method is presented for the extraction and analysis of water soluble ions from Teflon aerosol filters which is efficient and sensitive. This method uses a direct application of ethanol to the filter surface to decrease the surface tension of the filter and allow a dilute HC10, solution to contact the collection surface and extract any water soluble ions. This study compares this extraction method with other extraction methods currently being used. The results obtained from the extraction of water soluble ions from the Teflon filters were also compared to the results obtained from quartz filters collected on a colocated high volume sampler. From these studies, it is concluded that the hydrophobic nature of the Teflon filters makes the complete dissolution of water soluble ions exceptionally difficult and that the prewetting of the Teflon filters with ethanol minimizes dissolution and extraction problems.     

INAA of trace impurities in aluminium clads

As a contribution to nondestructive neutron assay of reactor grade aluminium, a number of elements have been investigated qualitatively and quantiatively using a vertical channel in the IRT-5000 reactor with a thermal neutron flux of 7.6·10¹²n·cm^–2·s^–1. The -ray spectra of irradiated samples were analysed with a 30 cm³ Ge(Li) detector connected to an HP-computer and a 4096 channel analyser. The following impurities have been determined: Sc, Ca, Cr, Fe, Ni, Co, Zn, As, Sb, W, Au, Th and U, while Lu and Hf have been determined qualitatively only.     

Detectors and detection limits in INAA

The kinetic behavior of deuteriation of 2-chloro-, 3-chloro- and 4-chlorobenzoic acids in the presence of homogeneous platinum salt catalyst in a medium containing solution of deuteriated acetic acid in heavy water has been studied at 130°C. The quasiunimolecular H/D exchange rate constants for particular position of aromatic ring hydrogens were determined by¹H NMR integration signal.     

Determination of phosphorus in polymers by INAA

An INAA technique employing beta spectrometry was developed for the determination of phosphorus in polymers. The (n,γ) reaction on phosphorus produces³²P, half-life 14.3 days, a pure beta emitter with end-point energy 1.71 MeV. Polymer samples in the form of powders, films and pellets are irradiated and then counted with a plastic scintillator. The beta spectrum is corrected for interferences (especially Sb, Zn and Br which are quantified by gamma spectrometry) and for energy loss in the thick sample. Samples must also be analyzed for S and Cl which cause nuclear interferences. With an irradiation time of 4 hours at a neutron flux of 5·10¹¹ n·cm^{−2 s −1}, decay time 10 days and counting time 10 minutes, the sensitivity is 520 counts/μg phosphorus and the detection limit is typically 2μg/g.     

Detectors and detection limits in INAA

Expressions have been derived which link detection limits in INAA with the Ge-detector specifications, provided by the vendors: relative efficiency, peak-to-Compton ratio and resolution. Situations have been distinguished in which a peak has to be detected on a Compton background, or on a natural background. The expressions allow for a direct indication of the improvement in detection limits, or the shortening of tumaround-time to attain equal detection limits, when a given detector is replaced by a detector with better specifications.     

Same nuclide interference corrections in INAA

Same nuclide interference (gamma emitting isotopes that are identical to the parent and/or daughter products of irradiation) corrections are discussed in INAA. The corrections account for production rate, decay, parent/daughter growth and equilibrium and the effect of the corrections on the reported uncertainties.     

南昌市农田土壤和水样中邻苯二甲酸酯污染物的分析

采用气相色谱-质谱联用的方法,研究了南昌市15处农田的土壤、地表水和地下水中4种常见邻苯二甲酸酯类物质的分布状况.结果表明,邻苯二甲酸二乙酯和邻苯二甲酸二(2-乙基己基)酯是南昌市农田的主要邻苯二甲酸酯污染物;土壤中邻苯二甲酸酯的检出率低于地表水和地下水.     

Non-Destructive Determination of Silicon in Steel and Steel-Related Samples by INAA Using the 29Si(n,p)29Al reaction

A non-destructive method has been developed for the determination of silicon in steel alloys by reactor fast neutron activation analysis using the ²⁹Si(n,p) ²⁹Al reaction. An iron sample and a comparator of pure metallic silicon powder are irradiated in a cadmium case. In order to obtain the net counting rate of the 1273.4 keV peak from ²⁹Al, background activities are corrected carefully to avoid peaks of 1268.0 keV from ²⁸Al single-escape and 1266.2 keV from ³¹Si. The present method is superior to the method using the ²⁸Si(n,p) ²⁸Al reaction.     

气溶胶、降水中的有机酸、甲磺酸及无机阴离子的离子色谱同时快速测定法

建立了梯度淋洗 ,在14min内同时测定大气气溶胶和降水中的甲酸、乙酸、草酸及大气中海洋微生物硫释放源指示物甲磺酸 (MSA)与无机阴离子F -、Cl-、 2-NO、 3-NO、 42-SO 、 3-4PO 的新方法 ;线性回归系数达0.9983～0.9998 ,分离度7.260 ,相对标准偏差在5 %以下 ,检出限(S/N=3)达1×10-8 (w) ,样品的加标回收率为80 %～120 % ;确定了不同滤膜采集的气溶胶的最佳浸提条件以及最佳色谱分离操作条件 ;此法已有效地应用于我国实地采集的气溶胶和降水的组分分析。     

Application of the INAA methods for KRISS infant formula CRM analysis: standardization of INAA at KRISS

We have established an instrumental neutron activation analysis (INAA) method, including k₀-based INAA, at the Korea Research Institute of Standards and Science (KRISS) for the certification of reference materials. As part of establishing INAA measurements, KRISS infant formula certified reference material was analysed for multiple elements at three different metrological institutes: KRISS and NIST for the standard comparator method, and JSI for the k₀-INAA method. The mass fraction of most elements was consistent within expanded uncertainty (k?=?2). In addition, the results were used to verify the validity of elemental analysis of Zn using the standard comparator INAA at KRISS, and spreadsheet-based INAA calculations were evaluated.

     

INAA of some phosphates used in fertilizer industries

INAA method for As, Br, Ca, Ce, Co, Cr, Eu, Fe, K, La, Lu, Na, Nd, Sb, Sc, Sm, Tb, Th, U, Yb and Zn determination in raw phosphates and Romanian NPK phosphate fertilizers was applied. The concentration values of uranium and some possible toxic elements in fertilizers are discussed.