What is the concentration range and detection limit for an ISE measurement?
These figures are given in the specifications for each ISE. In general it can be noted that most ISEs cannot be used for concentrations below about 0.1 ppm and many will only give a linear response and reasonable precision above 1 or 2 ppm. The upper concentration limit is usually quoted as 1Molar, but in practice it is difficult to obtain reliable results above about 0.5Molar because of uncertainties in the effect of high ionic strength on the activity coefficient.
