Abstract
Rapid oxidation of 0.5 to 2 mg organic samples by a flow combustion furnace has been investigated in order to improve the rapidity of the method for carbon-hydrogen microdetermination.
The diffusion process of a pulse fuel gas injected into a stream of gaseous oxygen was first observed by utilizing the rapid response of the color change of zinc chromite powder to the oxidation-reduction reaction at ca. 500°C. It was verified from the observation that not only a catalyst but also an oxidizing reagent were necessary to oxidize such a pulse sample even in a stream of oxygen because of an incomplete mixing of the sample gas with oxygen.
A copper-chromium oxide mixture was found to be much more superior as an oxidizing reagent in both the activity and the stability, which was supported by the X-ray diffraction and the life test. A flash combustion method using an aluminum foil capsule as a priming was developed for the instanteneous combustion of a solid sample.
Connecting the flash combustion furnace with a contact oxidation furnace, minor quantity of organic samples in any state was successfully oxidized in a short contact time of less than 11 sec.
