What is the effect of temperature change on ISE measurements ?
Unfortunately this is a complicated relationship which cannot be simply quantified in terms of mV change per C since the effect is different at different concentrations and actual value of the mV. Moreover, the electrode slope, the liquid junction potential, and solubility of the salts in the reference system all vary with temperature. However, the magnitude of the effect of temperature change on the slope can be calculated from a modified form of the Nernst equation (Slope = 2.303RT/nF = T x Constant) to be about 3.4% per 10C – ie: if the slope is about 55mV/dec then a 10C rise will increase this to about 57mV/dec. Thus, in order to avoid any errors due to temperature change it is advisable to recalibrate with standards at the same temperature as the sample solutions if the sample temperature deviates by more than about 2C from the original calibration temperature. Top 14.) How frequently should I re-calibrate the electrodes? This depends on the precision requirements for the results
