Analytical Chemistry in Medical Science and Technology. Ion-association titration of onium pharmaceuticals using tetrabromophenolphthalein ethyl ester as an indicator.

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Other Title
  • 医療と分析化学　　テトラブロモフェノールフタレインエチルエステルを指示薬とするオニウム系医薬品のイオン会合滴定
  • テトラブロモフェノールフタレインエチルエステル オ シジヤク ト スル オニウ
  • テトラブロモフェノールフタレインエチルエステルを指示薬とするオニウム系医薬品のイオン会合滴定(<特集>医療と分析化学)

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Description

Acrinol, cetylpyridinium chloride and benzalkonium chloride react with tetrabromophe-nolphthalein ethyl ester (TBPE) to form, blue ion associates. Also, dl-methylephedrine hydrochloride forms a red ion associate. Both associates can be quickly extracted into l, 2-dichloroethane. When sodium tetraphenylborate in a burette is dropped as a titrant, the onium compound remaining in the aqueous phase forms a colorless ion associate (R4N+ ·TPB-or R3NH+ ·TPB-) which is extracted quantitatively. At the end point, the tetraphenylborate anion takes the onium compound away from the colored ion associate in the organic phase and TBPEH, having a maximum absorption near to 400 nm, is dissociated. Consequently, the color of the organic phase turns to yellow. The color change in the organic phase provides a clear end point.

Journal

  • BUNSEKI KAGAKU

    BUNSEKI KAGAKU 46 (12), 951-955, 1997

    The Japan Society for Analytical Chemistry

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