Preparation Before pH Electrode Calibration

Before performing pH electrode calibration, three liquids need to be prepared: pure water, pH 7.00 standard buffer solution, and pH 4.00 standard buffer solution. These solutions are used for electrode cleaning and two-point calibration respectively.

pH calibration preparation solutions

pH Electrode Two-Point Calibration Operation Steps

Two-point calibration is a common method to improve pH measurement accuracy. It determines the actual percentage slope and zero point of the electrode through two standard buffer solutions. The following is the detailed operation process.

Step 1: Enter Calibration Menu

Find the Calibration option in the pH meter menu interface, and press the middle key to enter.

Enter calibration menu

Step 2: Select Two-Point Calibration Mode

Select the Two-Point Calibration mode. This mode uses two pH standard buffer solutions to calibrate the electrode system, and can measure the actual percentage slope and zero point of the pH composite electrode, effectively improving measurement accuracy.

Select two-point calibration

Step 3: Clean the Electrode

Thoroughly clean the electrode with pure water to remove surface residues and avoid contaminating the standard buffer solution.

Clean electrode with pure water

Step 4: First Point Calibration (pH 7.00)

After cleaning, press the OK key according to the interface prompt, and place the electrode into the pH 7.00 standard buffer solution. Wait for the system to prompt that calibration is complete, then proceed to the next calibration according to the interface prompt.

First point calibration pH7.00

Step 5: Second Point Calibration (pH 4.00)

Clean the electrode again with pure water, then place it into the pH 4.00 standard buffer solution for the second point calibration.

Second point calibration pH4.00

Step 6: Save Calibration Data

After calibration is complete, the display interface will prompt whether to accept the adjusted calibration data. Press the OK key to save the data of this two-point calibration.

Save calibration data

Calibration Precautions

  • Before changing the standard buffer solution each time, the electrode must be cleaned with pure water to prevent cross-contamination.
  • Standard buffer solutions should be freshly prepared or replaced regularly to ensure accurate pH values.
  • During calibration, the electrode must be fully immersed in the solution to avoid bubble attachment.
  • If high measurement accuracy is required, it is recommended to use multi-point calibration (such as three-point calibration).