DE-MASKING OF MAGNESIUM ACETYLACETONATE COMPLEX FOR DIRECT ETHYLENEDIAMINETETRAACETIC ACID TITRATION OF CALCIUM AND MAGNESIUM IN THE SAME SOLUTION AND AT THE SAME PH

A simple complexometric method, with ethylenediaminetetraacetic acid a s titrant, was developed for the determination of calcium and magnesiu m in a single aliquot of solution at pH almost-equal-to 10. The method involves determination of calcium at pH almost-equal-to 10, with use of a mixed indicator, after masking magnesium with acetylacetone at ro om temperature, followed by de-masking of magnesium at 90-degrees-C an d direct titration of magnesium at the same pH. The method was standar dized against synthetic solutions and applied to various calcareous ma terials, and the results were compared with those obtained by a standa rd method.