Abstract
An automatic analyzer for total carbon dioxide in decarbonated sea water was developed. The apparatus is based on the fact that electric conductivity of a potassium hydroxide aqueous solution changes by absorption of carbon dioxide discharged from the sample sea water.
The analyzer performs intermittent derminations at a half-hour cycle. Acid solution is added to a sample solution to lower the pH below 4, and the liberated carbon dioxide gas is led to the absorber, potassium hydroxide solution with nitrogen gas. Changes in electric conductivity of the absorber were proportional to the total carbon dioxide concentration of the sample.
Reliable determinations could be performed with a 200ml sample of 35% sodium chloride solution at room temperature under the following conditions: 300ml/min flow rate of nitrogen gas, 0.005N potassium hydroxide solution, less than 40 ppm total carbon dioxide in sample.
