Determination of Platinum-Group Elements (PGE) from catalytic converters in soil by means of docimasy and INAA

The nickelsulfide fire assay (docimasy) for the enrichment of platinum-group elements (PGEs) has been modified for the use with small samples and combined with instrumental neutron-activation analysis (INAA). This procedure has been applied to the determination of PGEs exhausted from catalytic converters and deposited in soil near the Wiesbadener Kreuz (highway A3, Frankfurt-Köln). Our results show a considerable enhancement of the Pt (up to 330 ng/g), Pd (6.6 ng/g) and Rh (7.5 ng/g) contents close to the highway.     

Determination of hafnium in zircaloy clad by means of INAA

Three reactions are described for the analysis of small concentration of Hf in zircaloy clads used for BWR and PWR reactor. One of the measurements is based on the measurement of short-lived^179mHf /18.7 sec/. The method is fast, selective, highly sensitive, non-destructive and has a detection limit of 1.3 ng for Hf.     

Determination of Platinum-Group Elements and Gold in Silicates by Gamma Activation Autoradiography and Instrumental Gamma Activation Analysis

The potential of the gamma activation determination of platinum-group elements and gold both by instrumental gamma activation analysis (bulk analysis) and by monitoring their distribution using autoradiography (local analysis) is studied. It is shown that platinum-group elements and gold can be determined by direct gamma-ray spectrometry in silicate samples with a detection limit of 10^–3–10^–5%. In contact gamma activation autoradiography, the detection limit for these elements is about 10 ng with a spatial resolution of 10–20 m.     

Determination of trace elements in hepatocyte of zinc deficient mice by means of INAA

Eleven elements in hepatocyte of mice fed with zinc deficient diet and those fed with control diet were determined by INAA. Zinc concentration, especially, in cytosolic fraction of zinc deficient mice was lower than that of control ones. On the other hand, cobalt concentrations in all fractions of zinc deficient mice were higher than those of control ones. However, when SDS-PAGE was performed for cytosolic fraction of hepatic cells, the positions and the number of the protein bands on gel developed for zinc deficient mice were not different from those for control ones.     

Determination of the Contents and Distribution Characteristics of Rare Earth Elements in Solanum lycocarpum from Tropical Ecosystems in Brazil by INAA

We have determined the concentrations of eight REE elements by instrumental neutron activation analysis (INAA) (La, Ce, Nd, Sm, Eu, Tb, Yb, and Lu) in plant leaves of the species Solanum lycocarpum, a typical Brazilian "cerrado" plant widely distributed around the country, and in the soils in which they grow. Three different ecosystems were studied. Very similar chondrite normalized patterns were observed in the soil and in the plant, presenting an enrichment of the light REE, indicating a typical absorption of these elements by this species.     

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.     

Determination of trace elements in reference materials by the k(0)-standardization method (INAA)

Instrumental neutron activation analysis was applied to four reference materials: NBS 1573 (Tomato Leaves), NBS 1645 (Citrus Leaves), NBS 1645 (River Sediment), and IAEA MA-A-2 (TM) (Fish Flesh). The k(0)-standardization method was used. The results are compared with (i) reference values (mostly non-certified) and (ii) published values obtained by other methods. Good agreement is found for most of the elements. For some elements, large discrepancies are observed.     

Enrichment factors and transfer coefficients from soil to rye plants by INAA

An extensive investigation of elemental levels in cereals and their cultivation soils has been going on across the main production areas of mainland Portugal, with a view to an eventual biofortification of major cultivars through agronomic practices. Cereals are an obvious choice as primary vehicles for food-supplementation programs, especially in countries where they definitely weigh in the dietary intake (like Portugal), and regions whose geographical and/or pedological features may account for nutrient deficiencies in typical diets. Mature rye plants (Secale cereale L.; roots and grains) and local soils were collected in the summer of 2009 from two regions of northern Portugal, and put through k ₀-standardized, instrumental neutron activation analysis (k ₀-INAA). Overall, the results (elemental concentrations, enrichment factors, transfer coefficients) seem to confirm an efficient uptake of elements from soil and their translocation to the aerial parts of the plants, notably to the ones that really matter in human nutrition (grains).     

Elements very rapidly measurable by INAA in biological and environmental materials

In connection with the increasing usage of reference materials in INAA work, and with the continuing interest in this laboratory in rapid analyses via very short-lived induced activities, 13 biological and 8 environmental reference materials have been processed, under rapid analysis conditions, by the reactor-flux INAA Advance Prediction Computer Program. The results described show that a total of 33 induced (n, ) activities of 26 elements are detectable in these 21 reference materials, in total analysis times ranging from 1.5 to 192 seconds.     

Determination of submicrogram amounts of selenium(IV) by means of the catalytic reduction of 1,4,6,ii-tetraaza- naphthacene

In the presence of glyoxal and hypophosphorous acid 1,4,6II-tetraazanaph-thacene is reduced to I,6-dihydro-I,4,6,II-tetraazanaphthacene. The reaction is catalyzed by selenium(IV). By means of this catalytic reaction, submicrogram amounts of selenium(IV) can easily be determined. The method is simple and sensitive, and there are few interferences.     

Determination of trace elements in honey by INAA in Turkey

Instrumental neutron activation analysis was applied to the determination of As, Cr, Sb, K, Br, Zn, Fe, Co in Turkish honey. Irradiation time was 6 h underwater at a thermal flux of 10¹³ n cm^–2 s^–1; cooling times of 100 h and 3–4 weeks and counting times of 5000 s and 80.000 sec were used. The detection limit for As is 0.01 ppm for honey matrix under these conditions. A technique was developed for sealing the quartz tube containing the honey with flame.     

Determination of rare earth elements in rice by INAA and ICP-MS

In order to improve the accuracy of reactor neutron activation analysis, flux gradients and spectrum changes in the irradiation capsule have been studied at the Kyoto University Reactor (KUR). The flux and spectrum monitoring samples of Fe, Co, Au, Sb, U and Ni were placed at several positions in a polyethylene irradiation capsule of 24 mm inner diameter and 98 mm length, and were irradiated in a pneumatic irradiation facility (Pn-2). The flux gradients were found to be rather negligible in the vertical (axial) direction while they were considerable in the radial one. The flux gradient was around 5%/cm for thermal neutrons and 10%/cm for epithermal and fast neutrons. The spectrum changes were dependent on the materials (polyethylene and silica) filled in the capsule. Based on these observations, the effect of the flux gradients and spectrum changes on the accuracy of reactor neutron activation analysis was discussed.     

Determination of total,and bound Se in sera by INAA

In this study we report on the comparison between the total selenium in serum (total Se) with that which is apparently bound to high molecular weight (>12,000 D) species, presumably proteins (bound Se). Nine hundred seventy seven (977) serum samples arising out of a population-based epidemiological study were prepared in duplicate for the determination of total Se by pipeting directly into irradiation vials; and separate duplicate aliquots were dialyzed against DI water for the determination of bound Se. All samples were analyzed by neutron activation analysis via^77mSe (17.4 s). A small dialyzable Se component (6%) (free Se), defined as the difference between the total Se minus the bound Se, was identified.     

Determination of REE by INAA in conodont apatite of Triassicage

Instrumental neutron activation analysis is applied to determine REE in very small, toothlike elements of an extinct animal, the conodont. The results are useful to obtain records of local oceanic events and processes connected to plate tectonics in the Tethys ocean from about 250 to 200 million years ago.     

Determination of dysprosium by INAA in some Bulgarian standard rocks

Dy content has been determined by INAA in the Bulgarian standard rocks BV, GV, DM, MrA, OgG, OZnO and in the IAEA standard reference materials SL-1, SOIL-5, and SOIL-7. Results are compared with Dy values obtained by interpolation of the chondrite-normalized contents of other REE in these samples.     

催化褪色光度法测定痕量钴

钴是人体健康不可缺少的微量元素，本文用酸碱指示剂间甲酚紫作为指示物质，催化动力学测定结果显示间甲酚紫在pH：10．0的NH3-NH4Cl缓冲溶液中呈紫色。Co(Ⅱ)对H2O2氧化这种紫色溶液褪色反应有催化作用，从而建立了测定钴的方法。该法可直接用于维生素B12和生物样品及地下水中Co(Ⅱ)含量的测定。     

Determination of trace elements in Wuxi fallen ice by INAA

The concentrations of 14 elements, including Ir, Au, Co, Cr, Fe, Sr, Rb, K, Ta, Zn, Sb, Ba, Sc and Se, in the Wuxi fallen ice were determined by neutron activation analysis. The experimental results show that the relative concentration ratios of Ir/Co, Ir/Cr and Ir/Sc etc. in the ice water (0.0069, 0.00024 and 0.11, respectively) are quite close to those of Type C1 chondrite (0.0102, 0.00021 and 0.092, respectively), which implies that the fallen ice might be a piece of extraterrestrial substance.     

Determination of vanadium(V) and molybdenum(VI) by means of a Landolt reaction

The determination of vanadium(V) and molybdenum(VI) by a Landolt-type reaction with bromate, iodide and ascorbic acid is reported. For the determination of vanadium(V) the molybdenum(VI) is masked with citrate-citric acid buffer, which also controls the pH. Molybdenum(VI) is determined in the presence of thiourea as masking agent for vanadium(V).