| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a COD automatic measuring instrument capable of preventing the deposit or the like of silver chloride to the surface of a sensor and capable of continuously measuring COD over a long period of time without being subjected to washing at every measurement. <P>SOLUTION: An ion concentration measuring part (A) for measuring the concentration of chloride ions of a sample solution is provided and the amount of silver nitrate added to the sample solution is determined on the basis of the concentration of chloride ions. When the amount of silver nitrate is a threshold or below, a silver nitrate solution is added to the sample solution in the amount equivalent to the determined amount of silver nitrate using an adding means and, when the amount of silver nitrate exceeds the threshold, the silver nitrate solution is added to the sample solution in the amount equivalent to the amount of silver nitrate exceeding the threshold using the adding means. Subsequently, the adding means (D) and (E) for adding the silver nitrate solution to the sample solution transferred to a reaction tank (C) from a reaction tank (B) in the amount corresponding to the threshold of silver nitrate using the adding means (E) are controlled, and COD of the sample solution is measured in the reaction tank (C) (G). <P>COPYRIGHT: (C)2009,JPO&INPIT |
