Experimental designs and response surface modeling applied for the optimization of metal-cyanide complexes analysis by capillary electrophoresis

The development of capillary zone electrophoresis (CZE) methods for the det ermination of metal cyanide complexes in real samples showed some problems, such as the low detection signal of Au (CN)(2)(-) and the low resolution b etween Ni(ll) and Fe(ll) cyanides in gold processing solutions, and the lac k of separation of Pt(CN)(4)(2-) and Pd(CN)(4)(2-) in the leachates from au tomobile catalytic converters. To optimize some analytical parameters, the present study thus focused on the application of experimental designs and m ultiregression models. The following factors were examined by a two-level f actorial design: applied voltage, injection time, detection wavelength, buf fer ion, ionic strength and buffer modifiers. For optimization of the CZE m ethod, subsequent response-surface experiments with the important factors w ere made with the two kinds of leaching solutions. Optimal analytical condi tions were obtained in each case, giving good detection signals and resolut ion for the components of the studied leachates.