3 Methods for the anal. of the amount of total organic C (TOC) in boiler feed water samples are presented and compared with each other.The 1st method is based on the UV absorption of organic compounds at λ = 254 nm.In the 2nd method, the organic compounds in the water samples are treated with UV radiation at λ = 254 and 185 nm and oxidized with persulfate.The oxidation product CO2 is determined with an IR detector.In the 3rd method, the organic compounds are combusted at temperatures between 680-1200°, and the resulting CO2 is again determined with an IR detector.