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

  Firouzeh Hassani Moghaddam - Department of Chemistry, Shahid Bahonar University of Kerman, Kerman, Iran Young Researchers Society, Shahid Bahonar University of Kerman, Kerman, Iran
  Mohammad Ali Taher - Department of Chemistry, Shahid Bahonar University of Kerman, Kerman, Iran

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

Alloys and biological samples, Separation, Cobalt Determination