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| Titel: |
Chemical equilibria and sequential extractive spectrophotometric determination of selenium(IV) and (VI) using the chromogenic reagent 4,4'-dichlorodithizone |
| Auteur: |
El-Shahawi, Mohammad S. Othman, Abdelhameed M. Bashammakh, Abdulaziz S. El-Sonbati, Mervat A. |
| Verschenen in: |
International journal of environmental analytical chemistry |
| Paginering: | Jaargang 86 (2006) nr. 12 pagina's 941-954 |
| Jaar: |
2006-10-15 |
| Inhoud: |
The chromogenic reagent 4,4'-dichloro(3-mercapto-1,5-diphenylformazan), Cl2H2DZ, forms a yellow-red-coloured complex with selenium(IV). The produced complex species was extracted quantitatively into n-hexane, and its absorbance was measured at 416 nm. The chemical composition of the extracted selenium(IV)-Cl2H2DZ chelate and the molar absorptivity at 416 nm were found to be [SeO (Cl2HDZ)2] and 9 × 104 L mol-1 cm-1, respectively. The values of the extraction constants (KD, Kex, β) enable a convenient application of the proposed system for the liquid-liquid extraction procedure and sequential spectrophotometric determination of traces of inorganic selenium(IV) and/or selenium(VI) after reduction of the later to selenium(IV) with HCl (6 M). Beer's law and Ringbom's plots were obeyed in the concentration range 0.01-20 and 0.5-19 µg mL-1 of selenium(IV), respectively, with a relative standard deviation of 2.2%. The proposed method has been successfully applied to the determination of selenium(IV) or (VI) and total inorganic selenium(IV) and (VI) in tap and freshwater samples. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 10 van 34 gevonden artikelen
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