Determination of Residual Organic Carbon of a Trace Concentration in High-purity Water by Continuous Liquid-phase O xidation

Abstract

An apparatus for the highly sensitive determination of residual organic carbon in highpurity water is described. Organic carbon in high-purity water is converted to carbon dioxide by chemical oxidation (K₂S₂O₈, 200°C, 30 kgf/cm²). The resulting CO² can be measured directly with a gas chromatograph. The amount of CO² is directly proportional to the concentration of carbonaceous materials in sample water. The analyzer developed consists of a degasser for removing the dissolved CO² in sample water, a reactor for converting organic material into CO², a gas/liquid separator for extraction of CO² in hot water and vapor, and a gas chromatograph for measuring CO² in extracting gas.
The dynamic range for the organic carbon determination was 1-100 ppb and the coefficient of variance at 1 ppb was 20%. The present analytical operation took 20 min per a sample.