Application of ethylenediaminetetraacetic acid as a titrant at high degrees of neutralization

Abstract

Alkaline ethylenediaminetetraacetic acid (EDTA) with degrees of neutralization α₀ in the range 0.950–0.990 was used successfully as a titrant for the determination of Mg²⁺(range 5 × 10^–3–100 × 10^–3 mol dm^–3) and other divalent cations. Sharp end-points can be obtained potentiometrically with a glass electrode and detected visually with phenolphthalein as indicator instead of Eriochrome Black T. Equilibria to interpret and calculate the potentiometric titration curves are presented.