Application of Doehlert optimization and factorial designs in developing and validating a solid-phase spectrophotometric determination of trace levels of cadmium

Using Response Surface Methodology (RSM) and based on sequential experiment al Doehlert designs, a Solid-Phase Spectrophotometric determination of cadm ium, at mu g/l level, with 4-(2-pyridylazo)resorcinol in the presence of po tassium iodide, has been established. The method has been characterized and validated by obtaining the performance characteristics. The IUPAC detectio n limit is 1.5 mu g/l and reproducibility (RSD) in the determination of 76. 0 mu g/l is 3.4%. Robustness was established using two-level saturated frac tional factorial designs. Selectivity was studied and trueness was confirme d with house reference materials. (C) 1999 Elsevier Science B.V. All rights reserved.