Open AccessA SOLID Fe2O3-GRAPHITE COMPOSITE ELECTRODE FOR pH MEASUREMENT
Author(s) -
Suchi Srivastava,
Raja Ram Pradhananga
Publication year - 2015
Publication title -
vaijñānika jagat
Language(s) - English
Resource type - Journals
ISSN - 1996-8949
DOI - 10.3126/sw.v12i12.13596
Subject(s) - palladium hydrogen electrode , quinhydrone electrode , glass electrode , electrode , potentiometric titration , standard hydrogen electrode , absolute electrode potential , reference electrode , reversible hydrogen electrode , working electrode , graphite , inorganic chemistry , ph meter , analytical chemistry (journal) , saturated calomel electrode , materials science , chemistry , electrochemistry , composite material , chromatography
A solid Fe2O3-graphite composite electrode was prepared and investigated for use as a potentiometric pH sensor. The electrode was constructed by mixing iron (III) oxide, oxidized graphite and wax that was put over silver disc onto a polypropylene rod. The response of the electrode was investigated by measuring electrode potential as a function of pH.The effect of composition of the electrode material (Fe2O3 and oxidized graphite ration) on the electrode response was investigated. The electrode with 40% Fe2O3, 30% graphite and 30% wax by mass was found to give the best potentiometric response. This electrode behaves in Nernstian manner with a potentiometric gradient of 56.6±0.4 mV per unit change in pH at 25?C within the working range of pH 2-9.The electrode was also used for the end-point detection in potentiometric acid-base titrations and found to be an excellent electrode for pH-metric titration. The effect of oxidation of electrode on pH response was investigated by dipping electrode in 0.1N KMnO4, 1:1HNO3 and 0.1N Ce4+ solutions for different interval of time. This treatment of the electrode with oxidizing agents increased the standard electrode potential of the electrode however potential gradient per unit change in pH remains unaltered. Low cost, quick response and easy to prepare are the advantages of the iron oxide - graphite composite electrode as a pH sensor. However some metal ions and oxidising agents interfered in the determination of pH using this electrode which is the limitation of using these electrodes.Scientific World, Vol. 12, No. 12, September 2014, page 44-47