Natural Monocrystalline Pyrite as Sensor for Potentiometric Redox Titrations. Part I. Titrations with Permanganate

Sensors

M.M. Antonijevic¹  R.P. Mihajlovic² 

[1] Technical Faculty Bor, University of Belgrade, P.O.Box 50, 19210 Bor, Yugoslavia;Faculty of Science, University of Kragujevac, 34000 Kragujevac, Yugoslavia

关键词: Pyrite;    Sensor;    Permanganate;    Potentiometry;    Reductants;   

DOI  :  10.3390/s20400153

来源: mdpi

【 摘 要 】

Results obtained in potentiometric titrations of Fe(II), Mn(II), Fe(CN)₆^4-, C₂O₄^2- and As(III) with standard potassium permanganate solution, are presented. The titration end point (TEP) was detected with a universal electrode whose sensor is natural crystalline pyrite. The titrations of As(III) were carried out in HCl (1.2 M) and H₂SO₄ solutions (0.1-4.5 M), whereas oxalate was determined in H₂SO₄ (0.1-4.5 M). Iron(II) and hexacyanoferrate(II) were titrated in H₂SO₄ and also in H₃PO₄ solutions (0.1-4.5 M). The titrations of Mn(II) were performed in H₂P₂O₇^2- media at pH 4.0, 5.0, 6.0 and 7.0. The results obtained by using the pyrite electrode were compared with those obtained by the application of a Pt-electrode, and good agreement, reproducibility and accuracy were obtained. The potentials in the course of the titration and at the end-point (TEP) are rapidly established. The potential changes at the TEP ranged from 90 to 330 mV/0.1 mL, depending on the titrated system. The highest changes were observed in titrations of Fe(II) in H₃PO₄ (240-330 mV/0.1 mL). Reversed titrations were also performed and accurate and reproducible results were obtained.

【 授权许可】

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