CALIBRATION OF pH METER SOP
5.4 Calibration of pH meter Frequency : Daily (Prior to use) 5.4.1 Before starting the calibration make sure that the correct measurement mode is selected. 5.4.2 Wash the electrode thoroughly with de-Ionized water or a rinse solution. Do not wipe the electrode; this causes a build-up of electrostatic charge on the glass surface. 5.4.3 Maintain the temperature of the buffers to 25°C ± 2°C, unless otherwise specified in the individual monograph and dip the electrode along with the temperature sensor into the buffers. 5.4.4 Perform the five point calibration using standard buffers of pH 1.68, 5.01/5.00, 7.00/7.01, 10.00/10.01 and 12.45. 5.4.5 Dip the electrode into the calibration buffer. The end of the electrode must be completely immersed into the sample. Stir the electrode gently to create a homogeneous sample. 5.4.6 Press CAL/MEAS key to enter pH calibration mode .The CAL indicator will be shown. The primary d...