A Reference Electrode for Electrochemical and Cryoelectrochemical Use in Tetrahydrofuran Solvent

✍ Scribed by Christopher A. Paddon; Richard G. Compton

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 92 KB
• Volume: 17
• Category: Article
• ISSN: 1040-0397
• DOI: 10.1002/elan.200503326

✦ Synopsis

Abstract

We report a reference electrode for direct use in tetrahydrofuran (THF) at low temperatures. A reference solution containing equimolar amounts of ferrocene/ferrocenium hexafluorophosphate (Fc/Fc^+^) are prepared to give a 4 mM solution in THF that contains tetrabutylammonium hexafluorophosphate (TBAF) supporting electrolyte thus, minimizing liquid junction potentials. The reference solution is added to a sealed glass tube with a porous frit at one end, and a platinum wire is inserted into the tube. The reference electrode assembly is then inserted into a THF test solution. Potentiometric measurements show that the system responds in the expected Nernstian fashion over the concentration and temperature ranges, 4 mM to 40 μM and 20 °C to −45 °C respectively. In addition, it is shown by steady–state cyclic voltammetry at a platinum microelectrode that the chemical reactivity of ferrocenium hexafluorophosphate (Fc^+^) otherwise seen in THF is suppressed by ion‐pairing with PF$\rm{ {_{6}^{-}}}$ using tetrabutylammonium hexafluorophosphate (TBAF) as the supporting electrolyte.