The end-point indication of chelatometric titrations by the decomposition of hydrogen peroxide catalyzed by lead(II) and copper(II)

Abstract

The application of the decomposition of hydrogen peroxide as exothermic indicator reaction catalyzed by lead(II) and copper(II), to catalytic thermometric endpoint detection of chelatometric titrations is described. The catalytic action of lead(II) is applied in ammonia-ammonium tartrate solution (pH 12), the action of copper(II) in ammonium carbonate (pH 8.8), sodium hydroxide-sodium carbonate (pH 10) and in ammoniacal medium (pH 12). The direct titration of EDTA, DCTA and NTA with copper(II) and lead(II), the invers titration of this metals, as well as the determination of several ions (Zn2+, Cd2+, Cu2+, Ni2+, Pb2+, Bi3+, In3+, Th4+) by backtitration has been developed. The ions mentioned can be determined in the milligram and in the microgram range with reasonable accuracy. © 1972 Springer-Verlag.