JPS6435260A - Chlorine ion concentration measuring apparatus - Google Patents

Abstract

PURPOSE:To measure the concentration of chlorine ions accurately, by detecting an electrode potential difference between an ion sensitive electrode using a substance sensitive to an interfering ion and a chlorine ion sensitive electrode using a quaternary ammonium salt. CONSTITUTION:When a chlorine ion sensitive electrode body 1 and a bromine ion sensitive electrode 6 are immersed into a sample, the chlorine ion sensitive electrode body 1 is sensitive to chlorine ions in the sample and bromine ions contained therein. Then, a voltage V1 proportional to the concentration of the chlorine ions and a potential V2 proportional to the concentration of the bromine ions are generated to output an electrode potential V1+V2 proportional to the sum of the concentrations thereof. On the other hand, the bromine ion sensitive electrode body 6 is not sensitive to the chlorine ion while it generates an electrode potential V3 proportional to the concentration for the bromine ion. The potential V3 is amplified with an amplifier at a fixed ratio to a potential V2. Thus, the concentration of the chlorine ions can be measured by detecting the potential difference V1 between both the electrodes 1 and 6.