Application of Doehlert designs in the optimization of experimental variables associated with the simultaneous solvent extraction of several metals

Abstract

An experimental design (Doehlert matrix design) has been carried out in this study to optimize the experimental variables for the simultaneous solvent extraction of Fe, V, Mo and Sn in isobutyl methyl ketone–tributyl phosphate with 5,5′-methylenedisalicylohydroxamic acid. Four variables were examined: pH and perchlorate, chelating reagent and synergistic agent concentrations. Two designs of two factors were performed, giving two response surfaces, one for each two factors. The plots of the analytical signalversus the experimental variables selected give two response surfaces which allow the optimum conditions to be identified for the quantitative extraction of the four metal ions. This optimization strategy is simple and quick, compared with the traditional univariate methodology.