Reference electrode external pressure-balanced

Lvov SN, Gao H, Macdonald DD (1998) Advanced flow-through external pressure-balanced reference electrode for potentiranetric and pH studies in high temperature aqueous solutions. J Electroanal Chem 443 186-194... 

With data on the activity of hydrogen ion in the standard solution available from model estimations, relatiorrships between the pH and cell potential, and hence a practical pH scale, for supercritical systems was developed. The potential of the cell comprising a pH sensor (yttria stabilized zirconia membrane) and a reference electrode (silver/silver chloride external pressure balanced electrode) (Emeas) can be written in the following form "... 

External pressure-balanced reference electrodes (EPBREs) have been developed and evaluated extensively over the past three decades. The first variant was described in 1978 by Macdonald et al. ° and was patented in the same year, with the invention being assigned to the Electric Power Research Institute. The electrode won the EPRI Invention-of-the-Year Award in 1979. The EPBRE that was first evaluated is described thermodynamically as the thermocell ... 

Figure 21. Assembly of an external pressure-balanced reference electrode (EPBRE). Reprinted from Ref. 50, Copyright (1992) with permission from Plenum.

All of the calculations described above correspond to Soret s initial state, i.e., to a state where the concentration of electrolyte along the bridge is constant. As noted above, maintaining the thermal junction in the initial state has been a vital problem in the operation of external pressure balanced reference electrodes. As also noted above, in the original design of the EPBRE (Fig. 21),... 

Using a similar concept, Sue et al." designed another flowthrough external pressure balanced reference electrode using a platinum/hydrogen electrode instead of Ag/AgCl electrode. The cell they developed can be depicted by ... 

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