Collect. Czech. Chem. Commun. 1991, 56, 1850-1855

Standardization of dilute solutions of EDTA by photometric titration with standard tetraamminecopper(II) titrant

Vladimír Mach, Stanislav Kotrlý and Václav Říha

Department of Analytical Chemistry, Institute of Chemical Technology, 532 10 Pardubice


Direct photometric titration (without an added indicator) using a standard ammoniacal solution of copper(II) prepared from pure copper metal asa primary standard is recommended as a reliable method for the standardization of Na2H2(edta) in 10-3 -5 . 10-4M solutions. The technique of photometric microtitration (720 nm, 50 mm cell) with an increased precision of transmittance reading (s ~10-2%, n > 7) and in optimum medium of pH 4.7 ± 0.4 (acetate buffer) can yield precise results in assays of EDTA (sr ⪬ 10-1%, n = 6-9).