Nitrato nitrosylruthenium complexes [RuNO (NO3) x (H2O) 5-x] (3-x) +readily dissociate in aqueous solutions with decrease in pH and increase in electrical conductivity of the solutions. This study aimed to elucidate the behaviours of dissociation of the complexes with time. The change in the amount of undissociated complexes was determined with time. The results indicated that the dissociation was a multi-order reaction involving both protolysis and hydrolysis. The protolysis completed in relatively short period within (several tens of minutes), but it depended on the concentration of the complexes in the solution. The completion of the protolysis and the formation of the resulting dissociation products were observed by absorption spectrometry. The dissociation products, which were assumed as aquohydroxy complexes, underwent the successive step-wise dissociation for a prolonged period as revealed by pH measurements. The rate constants involved in the step-wise dissociation, process were obtained. The degree of dissociation and dissociation constant of the complexes were measured by conductometry.
Formation cross sections and thick-target yields were studied in detail for alpha reactions and helium-3 reactions of natural cadmium in the energy range 10-40 MeV in order to determine the optimum condition for the production of medical use111In. The helium-3 reactions were found to give higher111In yield; namely, at the optimum helium-3 particle energy of 40 MeV and with the cadmium foil of 280 mg/cm2thickness the amount of111In produced was 270 μCi/μA⋅h. A cooling-time of 54 hours was required for the best radiochemical purity. The extraction of HBr-isopropyl ether followed by the anion exchange method was found to be the best chemical method for the carrier-free indium-111 separation.
A chelating agent-loaded resin consisting of 8-quinolinol-5-sulfonic acid and an anion-exchange resin (HOx-resin) was prepared in order to concentrate trace chalcophile elements in natural water samples selectively before neutron activation analysis. The exchange capacity of the Diaion SA# 100 for the reagent (1.8 meq⋅g-1resin) corresponds approximately to that for chloride ion (1.83 meq⋅g-1resin), indicating that 8-quinolinol-5-sulfonic acid is adsorbed quantitatively on the exchange site of the resin through the sulfonate anion in the reagent. The basic conditions for the adsorption of the metal ions on the resin were investigated by employing the column method. The nitrate concentration and the pH of the sample solution affect the adsorption behavior of metal ions. Several solutions containing metal ions with vary-ing pH or varying nitrate concentration were applied to the resin column (35 mm×7 mmφ) with a flow rate of 2.0 cm3⋅min-1. As a result, the optimum conditions for the quantitative adsorption of copper (II), zinc (II), cadmium (II), cobalt (II), nickel (II) and manganese (II) were as follows: NO3- <0.01 mol⋅dm-3pH >4.6. Furthermore, the feasibility of the above conditions as well as quantitative adsorption of the chalcophile elements was confirmed through the neutron activation analysis of the synthesized metal solutions.
Isolation and characterization of metabolites of miloxacin, a new antimicrobial agent, were undertaken with rats.14C-Miloxacin was orally administered to Sprague-Dawley rats at a dose of 50 mg/kg, and urine, bile and feces were collected. The metabolites extracted from the biological samples were isolated by column and thin-layer chromatographies. Characterization of the isolated metabolites was carried out by comparison with the authentic materials in various physicochemical analyses. Eight metabolites together with intact miloxacin were iden-tified; containing the metabolites of N-demethoxy (M-1), catechol (M-3) and 6-met hoxy (M-2 and M-4) types and their conjugates with glucuronic acid.