Formation and extraction of compounds tungstophosphate-thiazinic dyestuffs. Spectrophotometric determination of phosphate

Authors

  • C. Sánchez Pedreño
  • M. Hernández Cordoba
  • J.A. Ortuño
  • G.M. Tudela

Abstract

Phosphate anions don't form with basic dyestuffs extractable compounds. However the tungsto-phosphate associated to several dyestuffs are extracted with organic solvents. Between 0,2-10 p p m of orthophosphate is determined vía formation of the ion-association complex of tungsto-phosphate with the thiazinic dyestuff Azur B. The azur Btungsto- phosphate is extracted into benzene-cyclohexanone 1/1 v/v and the absorbance in this solvent measured a 645 nm. Optimal conditions for the determination have been established, and the effects of foreign ions have been examined. The determination is highly selective. The stoichiometry and structure of the ion-association complex has been studied.

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Artículos