Indexed on: 01 Jan '66Published on: 01 Jan '66Published in: Analytical and Bioanalytical Chemistry
A new method is described for the analysis of substances of lower oxidation states reacting with a KOH-melt to evolve hydrogen. Samples of 0.5 to 15 mg are introduced under vacuum into a degassed KOH-melt, whereupon all the substance dissolves in the form of the highest oxidation state and an amount of hydrogen equivalent to the content of the lower oxidation state is liberated. The gas evolved is pumped off, compressed with a Töpler pump, and its volume measured in a mercury gas-buret; it can also be identified by combustion over CuO. The composition of numerous NbOx-phases was determined in this way; in measuring non-stoichiometric compounds the limit of error may be characterized by the analytical composition NbO2.490±0.001. The oxidation-number of many oxides, halogenides and oxide-halogenides can be determined in the same way.