Simultaneous Determination of Cadmium and Lead in Real and Environmental Samples by Differential Pulse Polarography after Adsorption of Their 2-Nitroso-1-naphthol-4-sulfonic acid–Tetradecyldimethylbenzylammonium Ion-Associated Complex on Microcrystalline Naphthalene

Abstract

Cadmium and lead form 2-nitroso-1-naphthol-4-sulfonic acid–tetradecyldimethylbenzylammonium ion-associated complexes which are quantitatively adsorbed on microcrystalline naphthalene in the pH ranges 5.7–11.0 and 8.0–10.5, respectively. After filtration, the solid mass is shaken with 10 ml of 1Mhydrochloric acid and these metals are determined simultaneously by differential pulse polarography. The detection limits are 0.09 μg/ml for Cd and 0.10 μg/ml for Pb (signal-to-noise ratio = 2). Linearity is maintained in the concentration ranges 0.2–170 μg/ml for Cd and 0.3–270 μg/ml for Pb, with a correlation coefficient of 0.9996 and relative standard deviations of ±0.95 and ±0.90%, respectively. Various parameters such as the effect of pH, volume of the aqueous phase, and interference of a number of metal ions on the determination of cadmium and lead have been studied in detail to optimize the conditions for the simultaneous (based on the difference in theirEpvalues) determination of cadmium and lead in complex materials.