Simultaneous determination of mixtures of metal ions by complexometric titration and multivariate calibration

A new complexometric titration method for the determination of mixtures of metal ions with multivariate calibration was developed. The principle of this method is described and a linear complexometric titration equation is derived. In this work, a mercury film electrode (MFE) was used as indicator electrode for potentiometric measurements, and a double junction Ag/AgCl electrode as reference electrode. The mixtures of metal ions were titrated with ethylenediamine tetraacetic acid (EDTA), the titrant volume at each selected potential point was recorded and all these experimental data were then treated by multivariate calibration approaches, such as classical least squares (CLS) and partial least squares (PLS). Twenty synthetic mixtures with two-, three- and four-component combinations of lead, copper, zinc and cobalt with concentration levels from 5×10−4 mol l−1 to 1.5×10−3 mol l−1 were analyzed by the proposed method and acceptable results were obtained.