Study of monocolor spectrophotometric determination of lead, zinc and cadmium by dithizone extraction

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Other Title
  • ジチゾン抽出による鉛,亜鉛,カドミウムの単色比色定量法の検討
  • ジチゾン チュウシュツ ニ ヨル ナマリ , アエン , カドミウム ノ タンショク ヒショク テイリョウホウ ノ ケントウ

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Description

The mixed acid dissociation constant of dithizone has been determined spectrophotometrically in an aqueous solution having ionic strength 0.3 by extrapolating its apparent dissociation constants in several aqueous dioxane mixtures at 2528°C. This value was also confirmed by solvent extraction with n-hexane.<BR>The distribution coefficients of dithizone and its lead chelate between various organic solvents and water have been determined from the distribution ratios obtained experimentally.<BR>The complex formation constants of lead, zinc and cadmium with hydroxide, ammonia and cyanide, as well as 1 to 2 lead dithizonate, have been calculated from extraction data in order to apply the solvent extraction for analytical purpose.<BR>The quantitative extraction ranges with chloroform or carbon tetrachloride from a basic solution for lead, zinc and cadmium in monocolor method were shown in the figures, and analytical examples were given for zinc in under-ground water.<BR>The constants obtained were as follows (all in logarithmic unit); pKa, 4.34, distribution coefficients of dithizone:2.78 for n-hexane and 6.56 for chloroform, distribution coefficients of lead dithizonate:1.89 for n-hexane and 6.7 for chloroform, and for-mation constant of lead dithizonate β2=14.5.

Journal

  • BUNSEKI KAGAKU

    BUNSEKI KAGAKU 19 (10), 1333-1340, 1970

    The Japan Society for Analytical Chemistry

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