The nonaqueous titrimetric method for the determination of microamount of CO2 was introduced to determine oxygen in steel. Carbon monoxide extracted from a sample by the usual carrier-gas fusion method was oxidized with CuO at 750°C, and the dioxide produced was absorbed with N, N-dime-thylformamide containing 5% of monoethanolamine, and then titrated with the standard solution of tetra-n-butylammonium hydroxide in benzene-methanol. Satisfactory results could be obtained especially for the samples of low oxygen-contents. Sucrose was next investigated as a reference material to calibrate the instruments for the determination of CO or CO2. The definite amount of its standard solution was taken into a small gold boat and evaporated at 50°C in vacuo. The boat was then introduced into a small-mouthed graphite crucible heated at 1 900°C. Stoichiometric recovery of oxygen from the sucrose could be obtained under nearly the same extracting conditions as those for oxygen from steel samples. Thus, sucrose may be used as the reference material in order to calibrate the instruments for the analyses of both oxygen and carbon.
