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- Author or Editor: H. Maleszewska x
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Abstract
Distribution coefficients of Pt, Ir, Pd and Rh in the systems Dowex 1 [Br−]−HBr plus 0.0035M bromine and Dowex 1 [Br−]−HBr plus 2% N2H4·HCl, were determined with the aid of radioactive tracers by batch equilibration for the resins of nominal cross-linking 2, 4 and 8, respectively. Column experiments showed that Dowex 1X4 should be used for separations because of the favourable dynamics of the column process. Elution conditions for the quantitative separation of both trace and milligram amounts of Ir−Pt, Rh−Pt, Pd−Pt and Ir−Pd−Pt mixtures are given. Some data on the effect of temperature upon the quality of separation are also presented.
Abstract
Determination of trace impurities in platinum by neutron activation analysis was carried ont by combining the advantages of ion exchange chromatography and Ge(Li spectrometry. Owing to the development of a new ion exchange separation scheme which assures high decontamination factors with respect to matrix activities and practically quantitative yields, ppm and sub ppm amounts of Au, Cu, Ir, K, La, Mn, Pd and Zn were determined in 10 mg samples of pure platinum metal. No determinations of the chemical yield were necessary. Several other elements could be determined, if present, without essentially changing the procedure.
Abstract
Distribution coefficients of 14 elements between LIX 70 in toluene and aqueous 1M NaNO3 solution containing varying concentrations of HCl or suitable buffer, respectively, were determined by batch equilibration. It was shown that very selective separation of Cu from other elements can be achieved on columns with LIX 70 supported on Bio-Beads SM-1. Highly accurate and precise method for the determination of trace amounts of Cu in biological materials was devised by combining NAA with extraction chromatography. Results of copper determination in NBS 1570 /Spinach/, IAEA H-4 /Animal muscle/ and IAEA V-8 /Rye flour/ are presented.
Abstract
A highly accurate and precise procedure deserving the name of 
definitive method
has been devised for the determination of copper in biological materials. The method is based on combination of neutron activation and very selective and quantitative post-irradiation separation of copper from other radionuclides by extraction chromatography, using columns with LIX 70 on Bio-Beads SM-1, followed by gamma-ray spectrometric measurement. All potential sources of errors were carefully examined and eliminated or appropriate corrections were introduced into the procedure. The method contains several warning mechanisms safeguarding against making gross errors. Limit of detection for rather short irradiation time (tir
1 h) (which enables radiochemical work without sophisticated shielding) amounts to 15 
g/kg. Results for copper concentration in several NBS, IAEA and other certified reference materials are presented and a new recommended value for IAEA's Milk Powder (A-11) is proposed.
Abstract
Trace amounts of Ir, Au, Cu, Pd and Pt were determined in rhodium metal by instrumental neutron activation analysis with Ge(Li) spectrometry as well as by the radiochemical version of the method. The latter was based on a specially developed procedure of the dissolution of Rh, followed by group separation with the aid of ion exchange chromatography. The results obtained by destructive and non-destructive methods are critically discussed and compared. Special attention was paid to self-shielding effect and an accurate method of the correction of this effect is presented.
Abstract
Trace amounts of Ir, Au, Ag, Pt, Zn, Mn, and Cu were determined in high purity palladium by destructive and instrumental neutron activation analysis (NAA). The latter version of NAA was employed for the determination of Ir, Au and Ag. Special attention was paid to a new non-destructive method for the determination of silver traces in palladium. The results obtained by both versions of NAA are critically discussed and compared.
Abstract
Preparation and characterization of two new reference materials of biological origin, namely: Tea Leaves (INCT-TL-1) and Mixed Polish Herbs (INCT-MPH-2) is described. The raw materials were ground in an agate ball mill, sieved through a nylon sieve, collecting fraction of particle size: Æ£67 ·m, and carefully homogenized. Preliminary homogeneity testing by XRF method and final checking of homogeneity by NAA after distribution of the materials into containers revealed that they are sufficiently homogeneous at least for sample size ≥100 mg. Both materials were prepared in amounts exceeding 40 kg and certified on the basis of a worldwide interlaboratory comparison, in which 109 laboratories from 19 countries participated. The method of data evaluation leading to assignment of certified values was essentially the same as that used previously in this Laboratory, but supplemented by additional data from the analysis of a CRM which was sent to the participants and analyzed by them along with the candidate reference materials. In addition the results for a few elements by very accurate developed methods in this Laboratory were obtained and used to support the certification process. Analytical uncertainties and stability uncertainties were quantified to arrive at combined uncertainties of the certified values. So far 18 elements in INCT-TL-1 and 21 in INCT-MPH-2 could be certified.
