Summary
A new titrant, 1,2,4,6-tetraphenylpyridinium acetate, has been evaluated for the potentiometric precipitation titration of semimicro amounts of some large inorganic anions. Emf's were monitored with a perchlorate ion-selective electrode and a double-junction reference electrode. Satisfactory results were obtained for perchlorate, perrhenate, periodate, dichromate, permanganate, hexafluorophosphate, and hexachloroplatinate. Fluoroborate yielded a smaller endpoint break and poor precision. Thiocyanate, iodide, molybdate, tungstate, and tetrachloropalladate yielded partial or complete precipitation, but no analytically useful titration curves. We consider it likely that large anions such as pertechnetate, hexafluoro anions such as hexafluoroarsenate, and some complex metal chlorides such as those of mercury and tin (IV) can be determined in a similar fashion.
Zusammenfassung
Das neue Titrationsmittel 1,2,4,6-Tetraphenylpyridiniumacetat wurde zur potentiometrischen Fällungstitration von Semimikromengen einiger großer anorganischer Anionen herangezogen. Das Potential wurde mit einer selektiven Perchloratelektrode und einer doppeltverbundenen Bezugselektrode gemessen. Befriedigende Ergebnisse wurden mit Perchlorat, Perrhenat, Perjodat, Dichromat, Permanganat, Hexafluorophosphat und Hexachloroplatinat erhalten. Mit Fluoborat ergab sich ein schwächerer Endpunkt-Knick und geringere Genauigkeit. Thiocyanat, Jodid, Molybdat, Wolframat und Tetrachloropalladat ergaben teilweise oder vollständige Fällung, aber keine analytisch auswertbaren Titrationskurven. Wir nehmen an, daß sich große Anionen wie Pertechnetat, Hexafluoroarsenat u. dgl. sowie komplexe Metallchloride wie die des Quecksilbers und des Zinn(IV) in gleicher Weise bestimmen lassen.
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This work was performed under the auspices of the U. S. Energy Research and Development Administration, contract No. W-7405-Eng 48.
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Selig, W. Potentiometric semimicrodetermination of some anions with 1,2,4,6-tetraphenylpyridinium acetate. Mikrochim Acta 70, 75–81 (1978). https://doi.org/10.1007/BF01196469
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DOI: https://doi.org/10.1007/BF01196469