- GeoRef, Copyright 2006, American Geological Institute.
accuracy of analyses for organic carbon and nitrogen is affected by the temperature and time of combustion, and the oxidation agent used. Temperatures of combustion must be greater than 1,050 degrees C to give 95% of the true value. A temperature of 800 degrees C gives values 1/2 to / of the true value and a temperature of 500 degrees C gives values 1/4 to / of the true value. A combustion time of 30 seconds at 1,050 degrees C is satisfactory. As an oxidation agent, cupric oxide has slight advantages over oxygen.