Complexometric Analysis

 INTRODUCTION

A host of inorganic pharmaceutical substances essentially containing polyvalent and bivalent metal ions, for instance : Al3+, Ca2+, Mg2+, Bi2+ and Zn2+ were initially analysed quantitatively by the aid of gravimetric methods. These historically important procedures have become more or less obsolete since they are extremely time consuming and tedious owing to several steps involved e.g., precipitation, filtration, washing, drying and finally ignition to a constant weight.

 

Thereafter, analysis was done by faster techniques based on oxalate-permanganate titrations which involved a precipitation procedure followed by quick titration of pre-heated solutions containing oxalate ions.

 

More recently the introduction of an analytical reagent disodium ethylene-diaminetetraacetate, invariably termed as EDTA, an altogether latest titrimetric method has been used exclusively for the estimation of metals using metal-ion indicators.