Spectrophotometric extractive titrations-VI Titrations with 1-(2-pyridylazo)-2-naphthol.
The possibility of using PAN as a titrant in spectrophotometric extractive titrations has been investigated. Conditions suitable for the titration of zinc and of cadmium were found, with the aid of equations derived earlier and after investigation of the absorption spectra and pH- and reagent-dependence of the extraction of the chelates involved. For the purpose of spectrophotometric extractive titration of copper with PAN the formation and extraction of ion-association pairs CuPAN(+).Br(-) and CuPAN(+).CNS(-) were studied in detail. This titration was found to be highly selective. Dilute solutions of PAN in ethanol are much more stable than solutions of dithizone.
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Lachema, N.C., Kaznejov, Pilsen North, Czechoslovakia.