Extraction-spectrophotometric determination of potassium in river water with dibenzo-18-crown-6 and 4-((4-(phenylamino)phenyl)azo)-2,5-dichlorobenzenesulfonic acid.

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  • ジベンゾ‐１８‐クラウン‐６及び４‐〔〔４‐（フェニルアミノ）フェニル〕アゾ〕‐２，５‐ジクロロベンゼンスルホン酸を用いる河川水中のカリウムの抽出‐吸光光度定量
  • ジベンゾ 18 クラウン 6 オヨビ 4 4 フェニルアミノ フェニル アゾ
  • ジベンゾ-18-クラウン-6及び4-[[4-(フェニルアミノ)フェニル]アゾ]-2,5-ジクロロベンゼンスルホン酸を用いる河川水中のカリウムの抽出-吸光光度定量

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Abstract

An extraction-spectrophotometric method for the determination of potassium by means of a new reagent, 4-[(4-(phenylamino)phenyl)azo]-2, 5-dichlorobenzenesulfonic acid (TOOCl2) was proposed. The complexes of potassium ions with dibenzo-18-crown-6 (DB18C6) associate with TOOCl2 anions to give colored ion pairs which can be extracted into benzene. The ion pairs in benzene exhibit a maximum absorption at 430 nm with an apparent molar absorption coefficient of 9300 dm3 mol-1 cm-1. Potassium in river water was determined as follows: To a 50-cm3 vessel with a stopper, 5 cm3 of an aqueous TOOCl2 solution (0.02 mol dm-3), 5 cm3 of an aqueous Li2(EDTA) (0.001 mol dm-3) solution, and 10 cm3 of a water sample were transferred. The resulted solution was shaken with 20 cm3 of a benzene solution of DB18C6 (0.01 mol dm-3) for 30 min at 20°C. After the mixture was allowed to stand for 30 min, the absorbance of the benzene phase was measured at 430 nm against a reagent blank. Interferences from calcium (II) and magnesium (II) were avoided by complexing with EDTA. Sodium ions up to 8 ppm gave virtually no interference. Potassium concentrations determined by means of the proposed method agreed closely with those of atomic absorption spectrophotometry.

Journal

  • BUNSEKI KAGAKU

    BUNSEKI KAGAKU 34 (9), 579-581, 1985

    The Japan Society for Analytical Chemistry

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