(Ethylenedinitrilo) tetraacetic Acid Titration of Metal Ions. Polarized Mercury Electrodes

Successive determinations of calcium and magnesium in drinking water by complexometric, potentiometric digital titration to two equivalence points

“…The conditional sta-Flgure 4. Computed conditional stability constants for the Ca-EDTA complex and the Mg-EDTA complex as a function of pH: Pure solution (1, 2); 10-2 M 3,4-dihydroxybenzoic acid (3,4); 10~1 M 3,4-dihydroxybenzoic acid (5,6) Figure 5. Computed conditional stability constants for the Ca-EDTA complex and the Mg-EDTA complex as a function of pH: Pure solution (1, 2); 10-2 M acetylacetone (1, 3); 10~1 M acetylacetone (1,4) bility constant of the titrant ligand with respect to calcium ( Kca'L') must lie in the range 108-1010. The ratio between the conditional stability constants, •Kca'L'/íÍMg'L', must be approx.…”

“…10s. This ratio can be controlled by pH and the presence of a weakly binding ligand A (H"A-in this case: 3,4-dihydroxybenzoic acid or acetylacetone) according to the equation: Aca'L'/KMg'L' = -KcaL/AMgL «Mg/aCa (4) where, if reaction with A is assumed to be the only possible side reaction for the metal ion,…”

Successive determination of praseodymium and ytterbium by coulometric complexometric titration

“…A Pair of Polarized Mercury Electrodes and Polarized Current. The method of complexometric titration using a pair of polarized mercury electrodes in the presence of Hg-EDTA chelate has been investigated by Martin and Reilly (7). By use of a pair of polarized mercury electrodes as indicator electrodes, the largest break and shorter response time can be obtained.…”

Amperometric Titrations

“…with an applied potential of -0.7 volt. Martin and Reilley (76) used a single polarized mercury indicator electrode, or a bi-amperometric system of two mercury electrodes to titrate calcium or copper(II) with EDTA. The electroactive species is the mercury(II)-EDTA complex.…”