Fluorometric titration of calcium, magnesium and iron using calcein blue as indicator.
Calcium, magnesium and iron can be determined by successive fluorometric titration without separation. Calcium is titrated directly with EGTA at a pH 13; magnesium is determined by a substitution reaction with copper-EDTA complex at a pH of about 11 ; and iron is titrated directly with EDTA in the presence of hydrogen peroxide at a pH of 10.5, after destroying its triethanolamine complex. Calcein Blue serves as an indicator in all of the titrations and as a fluorescent standard. The end-points are sharp and the accuracy is good for various proportions of the metal ions. The method is simple, reproducible and inexpensive. Standard solutions of ions, limestone, cement and serum samples have been analysed by the proposed method.
Escarilla
A M
AM
Utica College of Syracuse University, Utica, New York, U.S.A.