Evaluation of the homogeneity of the environmental standard reference material — esturine sediment SRM 1646 by INAA and SRXRF

The distribution homogeneities of 13 elements (As, Ce, Co, Cr, Cs, Eu, Fe, Hf, La, Rb, Sc, Sm and Th) in the esturine sediment SRM1646 have been evaluated by INAA and synchronous radiation-based X-ray fluorescence spectrometry in the range of sampling amounts from 10 μg to 20 mg. The experimental results reveal that the homogeneities of the elements studied relate to their species and sampling amount. The sampling constants of these elements have been calculated.     

Methods for the preparation of mercury and osmium samples suitable for ion microprobe measurements

Using radiotracer solutions of Hg (²⁰³Hg) and Os (¹⁸⁵Os), techniques have been developed for sampling these elements presumably suitable for ion probe measurements. Mercury has been electrodeposited on the cross-sectional area (5 mm²) of an electrochemically pure Cu wire giving a recovery 25 to 30% at the tip. Similar efficiency is found for Hg distillate solutions. Osmium has been collected in a Ni–NiS bead after loading its thiourea complex solution on filter paper. The recovery in the bead is 80–90%. These methods should be of help for isotopic study of these elements by ion microprobe. The suitability of these samples for measurements remains unconfirmed.     

Comprehensive determination of trace elements in human saliva by ETA-AAS

A method is described for the comprehensive determination of a series of trace and ultratrace elements (Fe, Mn, Zn, Cu, Sr, Cr, Al and Si) in human saliva by atomic absorption spectrometry with electrothermal atomization and Zeeman-effect background correction. Procedures for sampling of total mixed saliva and its treatment including centrifugation and mineralization by HNO₃ are described in detail. To avoid the use of matrix modifiers, element standards with an artificial saliva matrix were used to construct calibration curves. Instrumental precision, tested by repeated analyses of natural salivas, is good (error less than 5%) for most elements. Lower precision was obtained for elements like Al and Si present in concentrations close to the detection limit. The analysis of some natural salivas clearly shows the influence of the sampling and treatment procedures on the reliability of the data. An accurate standardization of these procedures is thus recommended.     

Stock of immobilized metals in “José Antonio Alzate” dam mud sediment samples in the State of México, México

José Antonio Alzate dam mud sediment samples were collected from six sampling sites. The samples were analyzed by combining multielemental studies with structural details, including heating to very high temperatures. Characterization of mud sediment samples have been shown to have low concentrations of metals (Cr, Mn, Ni, Cu, Zn, Pb). No systematic trend was observed as a function of the sampling points.     

3D-SIMS analysis of ultra high purity molybdenum and tungsten: a characterisation of different manufacturing techniques and products

Applying a recently developed three dimensional SIMS imaging technique major differences in the distribution of trace elements in ultra high purity Mo and W have been found. In the electron beam melted material severe grain boundary segregation of trace elements have occurred whereas in the hot pressed material trace elements have been present as precipitates with a size of 5–15 m. Guided by the results of the 3D-SIMS images and the advantages of the sintering process a material with homogeneous distribution of trace elements has been developed and characterised. To test the applicability for the microelectronics industry, sputtering targets have been manufactured out of this new material and layers with a thickness of 350 nm have been sputterdeposited on silicon. The quality of these layers, with respect to particle emission and the distribution of trace elements, was evaluated by EPMA and 3D-SIMS imaging. Further improvement of the sintering process led to a material with a completely homogeneous distribution of C, H, N, O and S to minimise the outgassing and diffusion of impurities.Abbreviations BSE Back scattered electron - EPMA Electron probe micro analysis - GAAS Graphite furnace atomic absorption spectrometry - GDMS Glow discharge mass spectrometry - ICP-AES Inductively coupled plasma atomic emission spectrometry - ICP-MS Inductively coupled plasma mass spectrometry - SIMS Secondary ion mass spectrometry - ULSI Ultra large scale integration     

Determination of molybdenum, ruthenium, rhodium, and palladium in radioinactive simulated waste of the nuclear fuel cycle by solid sampling graphite furnace atomic absorption spectrometry (GFAAS)

Summary In relation with insoluble particles in the nuclear fuel cycle waste, the solid sampling GFAAS was used to determine molybdenum, ruthenium, rhodium, and palladium in such waste. Two methods for the direct determination of these elements are described. The samples must be handled in glove boxes or moreover in hot cells with a robot. The determination of the elements by the cup-in-tube technique needs a very sensitive balance (microbalance) for weighing in g-range and the handling of this method is not practical in glove boxes and hot cells.An alternative technique of solid sampling GFAAS, which can be used without great problems in glove boxes and hot cells is the slurry technique. In this case two methods have been used. One method uses graphite powder as a diluter, the other is the direct suspension of the sample in a matrix modifier solution. In the case of slurry technique with predilution of the sample with graphite powder, recoveries between 91 and 102% and RSD between 4 and 8% were obtained, whereas in the case of slurry technique with direct suspension of the waste sample recoveries between 91 and 103% and RSD between 14 and 20% for the above mentioned elements were obtained.

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Bestimmung von Molybdän, Ruthenium, Rhodium und Palladium in einem inaktiven Feedklärschlammsimulat mit der Feststoff-AAS

     

Direct solid vs. slurry analysis of tobacco leaves for some trace metals by graphite furnace AAS

Summary Graphite furnace atomic absorption spectrometry (GFAAS) is used to determine cadmium, lead, nickel and cobalt in two samples of tobacco leaves (candidate reference materials). Two techniques for the direct determination of these elements are investigated — direct solid sampling into a ring chamber tube specially designed for the Zeiss AAS-3 spectrometer and slurry sampling. For both investigated sampling methods the optimum parameters of temperature-time programs, influence of Pd modifier and calibration methods are discussed. There is acceptable agreement between the results obtained from direct solid, slurry and solution (after wet decomposition) sampling.Presented at the 4th International Colloquium on Solid Sampling with Atomic Spectroscopy, October 8–10, 1990; Jülich, Federal Republic of Germany     

Trace analysis of rare earth elements and other impurities in high purity scandium by inductively coupled plasma mass spectrometry after liquid-liquid extraction of the matrix

Bis(2-ethyl hexyl)-orthophosphoric acid in toluene has been used to extract scandium selectively from an aqueous phase containing nearly thirty elements at various concentrations. The trace elements (Li, Mg, Al, Mn, Co, Ni, Cu, Zn, Ga, Sr, Y, Cd, In, Sb, Ba, REE, Hf, Pt, Tl, Pb, Bi and u) have been determined quantitatively in the aqueous phase using inductively coupled plasma mass spectrometry (ICP-MS). The recoveries have been quantitative for most of the analytes studied and ICP-MS has been found suitable for the determination of trace quantities of these elements in the aqueous extract. The procedure has been applied to the quantitative ultra-trace analysis of rare earth elements (REE) and other trace impurities in high purity scandium metal (4N) using ICP-MS and ID-ICP-MS techniques.Presented in part at the 2nd Regensburger Symposium Massenspektrometrische Verfahren der Elementspurenanalyse, 6.-8.10.93, Regensburg, Germany