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

Abstract

Using Response Surface Methodology (RSM) and based on sequential experimental Doehlert designs, a Solid-Phase Spectrophotometric determination of cadmium, at μg/l level, with 4-(2-pyridylazo)resorcinol in the presence of potassium iodide, has been established. The method has been characterized and validated by obtaining the performance characteristics. The IUPAC detection limit is 1.5 μg/l and reproducibility (RSD) in the determination of 76.0 μg/l is 3.4%. Robustness was established using two-level saturated fractional factorial designs. Selectivity was studied and trueness was confirmed with house reference materials.