A: The XCell™ probe utilizes a silver/silver (I) chloride electrode in saturated KCl solution. Unlike the conventional copper-copper sulfate electrodes, the XCell™ electrode does not need changing the electrode solution. The electrochemical potential values measured by XCell™ are, however, shown based on the Cu/CuSO4 electrode according to the ASTM C876 specifications which state in section 5.1.1.3 that:
“Other reference electrodes having similar measurement range, accuracy, and precision characteristics to the copper-copper sulfate electrode may also be used. Calomel reference electrodes have been used in laboratory studies. For
concrete submerged in seawater, using silver-silver chloride reference electrodes avoids chloride contamination problems that may occur with copper-copper sulfate electrodes. Silver/silver chloride/potassium chloride reference electrodes are also applied to atmospherically exposed concrete. Potentials measured by reference electrodes other than saturated copper-copper sulfate should be converted to the copper-copper sulfate equivalent potential. The conversion technique can be found in Practice G3 and “Reference Electrodes, Theory and Practice” by Ives and Janz.”