Search Results

You are looking at 1 - 2 of 2 items for

  • Author or Editor: Shabnam Shahida x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract  

A very sensitive and selective flow injection on-line determination method of thorium (IV) after preconcentration in a minicolumn having XAD-4 resin impregnated with N-benzoylphenylhydroxylamine is described. Thorium (IV) was selectively adsorbed from aqueous solution of pH 4.5 in a minicolumn at a flow rate of 13.6 mL min−1, eluted with 3.6 mol dm−3 HCl (5.6 mL min−1), mixed with arsenazo-III (0.05% in 3.6 mol dm−3 HCl stabilized with 1% Triton X-100, 5.6 mL min−1) at confluence point and taken to the flow through cell of spectrophotometer where its absorbance was measured at 660 nm. Peak height was used for data analyses. The preconcentration factors obtained were 32 and 162, detection limits of 0.76 and 0.150 μg L−1, sample throughputs of 40 and 11 h−1 for preconcentration times of 60 and 300 s, respectively. The tolerance levels for Zr(IV) and U(VI) metal ions is increased to 50-folds higher concentration to Th(IV). The proposed method was applied on different spiked tap water, sea water and biological sample and good recovery was obtained. The method was also applied on certified reference material IAEA-SL1 (Lake Sediment) for the determination of thorium and the results were in good agreement with the reported value.

Restricted access

Abstract  

A flow injection on-line determination of uranium(VI) after preconcentration in a minicolumn having amberlite XAD-4 resin impregnated with dibenzoylmethane (DBM) is described. Uranium(VI) is selectively adsorbed from aqueous solution of pH 5.5 in the minicolumn (5.5 cm long with 5.0 mm i.d.) at a flow rate of 13.6 mL min−1. The uranium(VI) complex was desorbed from the resin by 0.1 mol dm−3 HCl at a flow rate of 4.2 mL min−1 and mixed with arsenazo-III solution (0.05% solution in 0.1 mol dm−3 HCl, 4.2 mL min−1), and taken to the flow through cell of spectrophotometer where its absorbance was measured at 651 nm. Various parameters affecting the complex formation and its elution were optimized. Peak height (absorbance) was used for data analyses. The preconcentration factors of 36 and 143, detection limits of 0.9 and 0.232 μg L−1, sample throughputs of 40 and 10 were obtained for preconcentration time of 60 and 300 s, respectively. The tolerance limits of many interfering cations like Th(IV) and rare-earth elements were improved. The proposed method was applied on different water (spiked tap, well and sea water) and biological samples and good recovery was obtained. The method was also validated on mocked uranium ore sample and the results were in good agreement with the reported value.

Restricted access