LIQUID ION-EXCHANGE ELECTRODES AS END-POINT DETECTORS IN COMPLEXIMETRIC TITRATIONS . DETERMINATION OF CALCIUM AND MAGNESIUM IN PRESENCE OF SODIUM

Chemical and potentiometric titration curves are derived based on theoretical assumptions, for EGTA and DCTA as titrants. The problem of locating the equivalence point on practical titration curves is discussed. Linear extrapolation methods are outlined that should enable this point to be determined more accurately. It is concluded that compleximetric titrations monitored with liquid ion-exchange electrodes such as the Orion calcium activity electrode and divalent electrode should be useful for the analysis of calcium and magnesium in natural waters. © 1969.