Derivative UV-visible spectrophotometric determination of nickel in alloys and biological samples after preconcentration with the ion pair of 2-nitroso-1-naphthol-4-sulfonic acid and tetradecyldimethylbenzylammonium chloride onto microcrystalline nap

摘要

Nickel is quantitatively retained by tetradecyldimethylbenzylammonium 2-nitroso-1-naphthol-4-sulfonate in microcrystalline naphthalene in the pH range 7.2-11.8 from a large volume of aqueous solutions of various alloys and biological samples. After filtration, the solid mass consisting of the nickel complex of 2-nitroso-1-naphthol-4-sulfonate and naphthalene was dissolved in 5 mi of dimethylformamide and the nickel as determined by first derivative UV-visible spectrophotometry. Nickel can alternatively be quantitatively adsorbed on a 2-nitroso-1-naphthol-4-sulfonic acid-tetradecyldimethylbenzylammonium-naphthalene adsorbent packed in a column and determined similarly. The detection limit is 0.3 mu g ml(-1) (signal to noise ratio=2) and the calibration graph is linear over the concentration range 0.9-120 mu g ml(-1) in dimethylformamide solution with a correlation coefficient of 0.9995 (n=6) and relative standard deviation for 8 mu g ml(-1) nickel of 1.4% (n=6), Various parameters such as the effect of pH, volume of aqueous phase and interference of a number of metal ions on the determination of nickel have been studied in detail to optimize the conditions for determination in standard alloys and biological samples. (C) 1998 Elsevier Science B.V. [References: 17]