FAAS DETERMINATION OF COBALT AFTER SEPRATION BY USE OF 1-NITROSO-2-NAPHTHOL-3,6-DISULFONATE

Cobalt was quantitatively retained by disodium 1-nitroso-2-naphthol-3,6-disulfonate (nitroso-R salt) and tetradecyldimethylbenzylammonium chloride on microcrystalline naphthalene in the pH range 3.6 - 8.2 from large volumes of aqueous solutions of various alloys and biological samples. After filtration, a solid mass consisting of the cobalt complex and naphthalene was dissolved with 5 ml of dimethylformamide (DMF), and the metal was determined by flame atomic absorption spectrometric (FAAS). The cobalt complex could alternatively be quantitatively adsorbed on tetradecyldimethylbenzylammonium-naphthalene adsorbent packed in a column and determined similarly. In this case, 0.50 g of cobalt can be concentrated in a column from 500 ml of aqueous sample, where its concentration is as low as 1.0 ppb. Eight replicate determinations of 1.0 ppm of cobalt gave a mean absorbance of 0.050 with a relative standard deviation of 1.9%. The sensitivity for 1% absorption was 88 ppb.Various parameters, such as the effect of the pH, the volume of the aqueous phase and the interference of a number of metal ions on the determination of cobalt has been studied in detail to optimize the conditions for the determination cobalt in various alloys and biological samples

کلیدواژه ها:

Alloys and biological samples ، Separation ، Cobalt Determination