METHOD AND APPARATUS FOR DETERMINING QUATERNARY AMMONIUM SALT USING CARBOXY ION AS PAIRED ION

PURPOSE: To provide a method and apparatus for determining quaternary ammonium salt simple to adapt, having general-purpose properties and excellent in reproducibility. CONSTITUTION: An indicator soln. prepared by dissolving an indicator having a sulfonic acid group and hydroxy group as functional groups in a solvent is dripped to a sample soln. dissolved in a solvent to perform titration reaction. The relation between titration quantity and conductivity is plotted with respect to the first stage of titration reaction forming an indicator wherein both of the sulfonic acid group and the hydroxyl group are simultaneously ionized by the reaction of the indicator and a quaternary ammonium salt epoxy compd. and carboxylic acid and the second stage of titration reaction forming an indicator wherein only the sulfonic acid group is ionized by the reaction of the indicator and the ionized indicator. From the titration quantity at the intersecting point of the straight line connecting the plots in the first stage and the straight line connecting the plots in the second stage, the amt. of a quaternary ammonium salt is calculated.