How to Calibrate a pH Meter

PH meter is a commonly used instrument and equipment. It is mainly used to precisely measure the pH value of liquid medium. It can also measure the MV value of ion electrode potential with the corresponding ion selective electrode. It is widely used in industry, agriculture, scientific research, environmental protection and other fields. . The instrument is also an essential inspection equipment for QS and HACCP certification in food factories and drinking water factories. When the instrument is in continuous use, it should be calibrated once a day. Unplug the Q9 short-circuit plug from the measuring electrode socket; plug the compound electrode into the measuring electrode socket; if the compound electrode is not used, plug the electrode converter plug into the measuring electrode socket; insert the glass electrode plug into the converter socket; refer to The specific electrode is connected to the reference electrode interface. After the power is turned on, press the 'pH/mV' button to make the instrument enter the pH measurement state and preheat for 30 minutes. Press the 'Temperature' button to display the humidity value of the solution (at this time the temperature indicator light is on), then press the 'Enter' button, the instrument will return to the pH measurement state after confirming the solution temperature. Insert the electrode cleaned with purified water into the standard buffer solution with pH=6.86 (25°C), and press the 'Position' button after the reading is stable (at this time, the pH indicator flashes slowly, indicating that the instrument is in the state of positioning and calibration) to make the reading as The pH value of the solution at the current temperature; then press the 'OK' button, the instrument enters the measurement state, and the pH indicator light stops flashing. Insert the electrode cleaned with purified water into the standard buffer solution with pH=4.01 (25°C) (or pH=9.18 (25°C)), and press the 'Slope' button after the reading is stable (at this time, the pH indicator flashes, indicating that The instrument is in the slope calibration state), so that the reading is the pH value of the solution at the current temperature, and then press the 'OK' button, the instrument enters the pH measurement state, the pH indicator light stops flashing, and the calibration is completed. Repeat steps 5 to 6 until the difference between the value displayed by the instrument and the pH value of the standard buffer solution is ≤±0.02 without adjusting the two adjustment knobs for positioning or slope. Don't look at so many steps, it's actually quite simple, just try a few more times to become proficient