Abstract: For the quantitative determination of the total oxygen demand of water containing oxidizable matter, the water is continuously evaporated at about 900.degree. C. in the presence of varying amounts l.sub.1, . . . , l.sub.n of oxygen-containing gas added per unit of steam at continuously repeated intervals. The oxygen-containing gas should not exceed 1 to 5% by volume, calculated on the amount of steam produced during each interval. The residual oxygen concentrations S.sub.1, . . . , S.sub.n in the steam gas/mixture are measured for the different amounts of oxygen-containing gas added and the oxygen demand is calculated from the residual concentrations and the added amounts of the oxygen-containing gas.

Abstract: In the determination of the quantity of carbon present in water in the form of organic compounds the carbon-containing water is first evaporated in the presence of oxygen at a temperature of about 900.degree. C. Care must be taken that the oxygen does not exceed 1 to 5 volume %, calculated on the quantity of steam. Then the CO.sub.2 content is measured with a CO.sub.2 analyzer. In a second step the carbon-containing water is measured without oxygen under identical conditions. The quantity of carbon present in water in the form of organic compounds is determined from the measured CO.sub.2 concentrations.