Simultaneous spectrophotometric determination of copper(II) and nickel(II)as complexes with sodium diethyldithiocarbamate in an anionic micellar medium using partial least-squares regression

A spectrophotometric method for the simultaneous determination of copper an d nickel by the use of diethyldithiocarbamate (DDTC) as a chelating agent i n the presence of aqueous anionic micellar medium of sodium dodecyl sulfate (SDS) was developed. The presence of micellar systems allow one to elimina te the solvent extraction step necessary for the determination of metal-DDT C complexes in the absence of micelles. This reduces the cost and toxicity of the method. The influence of chemical variables affecting the analytical reaction was evaluated. A partial least-squares procedure was used to acce ss data obtained from the calibration solutions. The ensuing method was val idated by applying it to the analysis of synthetic mixtures over the concen tration ranges 0-286 mu mol Cu/ml and 0-619 mu mol Ni/ml. The relative erro rs in determinations were less than 5% in most cases. The proposed method w as applied to the determination of Cu and Ni in metal alloys. (C) 1999 Acad emic Press.