[en] Methods for the determination of chloride in molybdenum, tungsten, niobium and tantalum and of phosphorus in molybdenum and tungsten are presented. After oxidative digestion the analytes are separated from the matrix and accumulated in a small volume of liquid. Unsuppressed ion chromatography serves as the final determination method. The trace-matrix-separation and enrichment of chloride is largely independent of the kind of matrix. The procedure is therefore also applicable to concentrated solutions of various salts. A closed system ensures chloride blanks around 0.2 ppm and detection limits in the higher ppb range. A modification allows an enrichment of bromide and the simultaneous determination of chloride and bromide. (orig.)

[en] The electrolytic behaviour of plutonium ions in a mixture of phosphate and nitrate solutions was studied by flow-coulometry with column electrodes of glassy carbon(GC)-fibers and voltammetry with a GC disc electrode, and compared with that in phosphate-free media. The redox processes, PuO₂²⁺/PuO₂⁺ and Pu⁴⁺/Pu³⁺, were demonstrated to be reversible even in the phosphate media and their half wave potentials shifted more negatively due to the formation of PuO₂(H₂PO₄)⁺ and Pu(HPO₄)₂. The rate of the irreversible reduction of PuO₂⁺ to Pu³⁺ increased in the presence of phosphoric acid and the quantitative reduction was attained with the column electrode even at +0.35 V vs. saturated KCl-Ag/AgCl. The reduction process of PuO₂⁺ was elucidated considering an intermediate Pu(IV)-species, PuO²⁺, which decomposed into Pu⁴⁺ by a post-chemical reaction. Analytical advantages of the use of phosphate media are discussed. (orig.)

[en] The direct instrumental methods X-ray fluorescence spectrometry (XRFS) and instrumental neutron activation analysis (INAA), and, after digestion of the sample, inductively coupled plasma mass spectrometry (ICP-MS) were applied in sequence to analyse small single aerosol filters. XRFS detected up to 19, INAA up to 22, and ICP-MS up to 33 elements. In total, up to 45 elements were determined, and, for a number of additional elements limits of detection could be given. For many elements, the data quality could be checked by cross-comparison of the results of two or all three methods. These methods very meaningful complement each other and, in the manner used, allow the determination of all elements of interest in a small aerosol filter sample. (orig.)

[en] It has been observed that the results obtained by the thiocyanate-stannous chloride method for the determination of small amounts of rhenium, are often not reproducible because of serious interference by various metal ions. Though several improvements have been suggested from time to time, the problem still persists. We have therefore made an attempt to effect further improvement by the use of benzoyl acetone in addition to thiocyanate. (orig.)

[en] 0.05 to 25 μg/g of vanadium in iron was determined by inductively coupled plasma atomic emission spectrometry after solvent extraction using N-benzoyl-N-phenylhydroxylamine-chloroform solution. Vanadium extracted in the chloroform phase was finally transferred into perchloric acid solution and sprayed into the ICP. The analytical line and the corerection line for variation in spectral intensity were V II 309.311 nm and Y II 371.030 nm, respectively. Standard deviation and detection limit were 0.03 μg and 0.1 μg. (orig.)

[en] Additional application work has been carried out in order to demonstrate further possibilities of the combination Atomsource/AAS for the determination of trace elements in microgramme samples. The method was tested in routine application for different elements like Cu, Nb or Zr. Moreover, a very simple method of mercury determination allowing the detection of 1 ng Hg in 1 μg sample material is described. The technique permits direct analysis of dust, soil, and other oxide samples collected in microgramme amounts for several elements. (orig.)

[en] Large soil samples (up to 500 g) can conveniently be disintegrated by hydrogen peroxide in an utility tank under alkaline conditions to determine subsequently ¹²⁹I by neutron activation analysis. Interfering elements such as Br are removed already before neutron irradiation to reduce the radiation exposure of the personnel. The precision of the method is <10% (1 RSD). The accuracy was checked by determining ¹²⁹I also by the combustion method. (orig.)

[en] The great usefulness of reference materials, especially ones of certified elemental composition, is discussed with particular attention devoted to their use in instrumental neutron activation analysis (INAA) work. Their use, including both certified and uncertified values, in calculations made by the INAA Advance Prediction Computer Program (APCP) is discussed. The main features of the APCP are described, and mention is made of the large number of reference materials run on the APCP (including the new personal computer version of the program), with NBS Oyster Tissue SRM-1566 used as the principal examle. (orig.)

[en] Vanadium (III), obtained by sodium dithionite reduction of vanadium (V), forms a coloured complex with picolinic acid which is extracted into chloroform from slightly acidic medium. The method is free from interference by relatively high concentrations of analytical important elements such as iron, cobalt, nickel, zinc, copper, titanium, aluminium, chromium, molybdenum, tungsten and uranium. The proposed method of separation is simple and rapid and its applicability has been tested by the satisfactory recovery of vanadium from a variety of synthetic and natural samples. (orig.)

[en] The limitations of direct trace determinations in high purity niobium by ICP-AES and ICP-MS are evaluated. Further improvement of the detection limits requires previous trace-matrix separations. A batch procedure with cellulose-Hyphan as collector and a column procedure with a cation exchange resin are described. The latter is less prone to contaminations and more suitable for routine applications. (orig.)