Determination of pH of Solutions at Low Temperatures with the IrO_x/Ti Electrode

IrOx/Ti electrode was prepared, and influences of change of temperatures to its sensitivity of response, time of response and its potential response were studied. It was found that the value of reponse of the electrode in an ethanol freezing-proof liquor at -20 ℃ was only 2.52 mV·pH-1 lower than the value obtained at 30 ℃. Based on this fact, this electrode was applied to the determination of pH values of freezing-proof liquor systems at low temperatures; and in the determination of pH values of NaCl solutions at -10 ℃, values of relative extreme difference and relative average deviation obtained were 1.8% and 0.6% respectively.