Performance and reference potential of the calomel electrode with aqueous CsCl bridge

PH-metric and pIon-metric controls for both scientific and routine purposes can benefit from appropriate modifications in the ref. electrode structure. Changing from the old Hg|Hg2Cl2|4.8 m (sat) KCl configuration to the new Hg|Hg2Cl2|4.8 m CsCl configuration, the working potential of the calomel ref. electrode changes very little (from 0.2444 to 0.2448 V at 25°) but the performance is much improved because the built-in 4.8 m CsCl bridge (contrary to the old KCl one) is highly efficient in zeroing the residual liq. junction potential, as ensured by the nearly exact equitransference of aq. CsCl over the whole range of concns. A further advantage, offered by the CsCl bridge, lies in the possibility of using even higher working concns., the CsCl satn. being reached at 11.3 mol/kg at 25° and even more at higher temps.