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A New Spectrophotometric Method for the Determination of Uranium (VI) and Thorium (IV) in Diversified Rocks Using the Chromogenic Calcon Dye |
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PP: 141-155 |
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Author(s) |
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Shaimaa Salah Abdulmoteleb,
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Abstract |
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| Calcon dye is recommended as a chromogenic reagent in a precise and sensitive spectrophotometric approach
for the detection of U(VI) and Th(IV). Calcon serves as a complexometric indicator for Al, Fe, and Zr. When combined
with acetate buffer, the metal ions (U and Th) and calcon dye form a complex instantly at pH 4 for U (VI) and pH 3 for Th
(IV). For two hours, the (U and Th) complex is stable. Peak absorbance (λmax) for U (VI) and Th(IV) in the complexes is
682 nm and 658 nm, respectively. The molar ratio for U- calcon and Th- calcon was 1:1 for each complex. Using XPS
analysis, the preliminary complexation mechanism was verified. The impact of acid type, appropriate buffer pH, dye
concentration, molar ratio, calibration curve, and tolerance limits of certain interfering ions are among the parameters of (U
and Th) that are investigated in this work. For U (VI) and Th (IV), the average molar absorptivity (Ɛ) was found to be
0.89×104 L M−1 cm−1
and 0.67 × 104 L M−1 cm−1
, respectively. Beers law was applied and verified between 0.1 and 15 µg
U m L−1
and 0.25 and 20.00 µg Th m L−1
. Using solid ammonium chloride and ammonia solution to precipitate various
ions throughout the determination process improved the selectivity of this approach. U(VI) and Th(IV) in internationally
certified standard materials (Nim G, BL-2a, and DL-1a) as well as reference samples were successfully determined using
the suggested method. The accuracy and precision (RSD <1%) were met with satisfaction. |
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