Application Note: pH Measurement of Pure Water: Performance of Specialist Sensors
11 March 2019

The measurement of pH in pure water samples is critical due to its low conductivity, fluctuations in liquid junction potential of electrode, and also lack of sensitivity of glass membrane. Pure water can be defined as water samples with a conductivity of less than 100 µS/cm. These pure water samples are low in both hydrogen ions and conducting ions. Low ionic concentration of the sample deters a stable liquid junction potential in the pH electrode system.  Using specialist laboratory pH sensors from METTLER TOLEDO eases pH measurement in such low ionic water samples. The following study is a technical approach to measure pH in low ionic water samples using pH sensors of various types including specialist sensors.