Radiochemical neutron activation analysis of high pure palladium and platinum by ion exchange chromatography

Full text: The palladium and platinum are widely used for jewel manufacture because of their beautiful white color. However the most part of these metals are widely adopted in the world as catalysts. Many works on analytical chemistry of platinum group elements published during last years are devoted to determination of platinum and palladium in other materials. There are no articles on analysis technique of the palladium and platinum purity published during last 20 years. Available publications are very old and are published till 70th of the last century, and implement chemical and spectral methods. At the same time, the palladium and platinum are very suitable for NAA. Therefore the purpose of our research was development of high-sensitivity and multielement techniques of radiochemical neutron activation analysis of a high pure palladium and platinum. Research of nuclear characteristics of palladium and platinum has shown that radioactive nuclides with different yields are formed under the reactor neutrons. 109, 111, 111mPd, 109m, 111Ag, 191,197, 199Pt, 199Au are the most important among them. 109Pd separation factor is equal to 1*105 at palladium analysis, whereas 197Pt and 199Au separation factor is equal to 1*104 at the platinum analysis every other day after irradiation. Palladium and platinum can be separated by precipitation, extraction and ion exchange methods. For separation of radioactive nuclide of the matrix elements from the impurity elements we used ion exchange chromatography system Dowex-1x8 - 1 M HNO3 for palladium and Dowex-1x8 - 0.1 M HNO3 for platinum. At the HNO3 acid concentrations variation from 0,1 M to 1 M more then 25 elements have distribution factors less than 1 and 10 elements have distribution factors 5 while matrix elements have distribution factors higher than 100. It allows an effective separation of these elements from palladium and platinum. Optimum sizes of the chromatographic column and the column effluent volume was obtained by elution curve of the determined elements and distribution profile of the matrix elements. Chemical yields of determined elements were measured by 'entered - found' method. Chemical yields of Sn is 31.2%; Zn is 54.5%; Se is 74.%1, and for other elements it is more than 85 %. Based on the carried out researches the radiochemical neutron activation analysis techniques of a high pure palladium and platinum are developed. These techniques allow determination of more than 30 elements with detection limits 10-5-10-9 % with Sr 0.15-0.2. (author)