Methods and apparatus for measurement of the carbon and heteroorganic content of water including single-cell instrumentation mode for same

Apparatus and methods for determining the content of total organic carbon, total inorganic carbon, total carbon and total heteroorganic carbon in water are disclosed. In a preferred comprehensive embodiment, the water sample is split into a first stream and a second stream. Inorganic carbon in the first stream, if any, is determined by acidifying the sample, measuring the electrical conductivity using a temperature and conductivity sensor, and removing the ionic species. Organic carbon in the first stream is then substantially completely oxidized in a U.V. oxidation reactor to carbon dioxide and possibly other oxidation products, and the electrical conductivity of the effluent- stream is measured using another temperature and conductivity sensor. At least a portion of the carbon dioxide in the first stream is transferred through a carbon dioxide permeable membrane into the second strewn. The second stream then passes into another temperature and conductivity sensor and conductivity is measured. Total carbon content, inorganic and organic carbon, and, if present, the heteroorganic organic content of the sample can be determined from the various conductivity measurements.