Blog Details

A pH sensor is a critical device for measuring the acidity or alkalinity of liquids, and its accuracy and stability are vital for reliable production and research outcomes. Regular maintenance and calibration are essential to ensure optimal performance. Below are detailed steps for maintaining and calibrating a pH sensor:

‌I. Maintenance of pH Sensors‌

‌Electrode Storage and Protection‌

• • Avoid leaving the sensor’s glass electrode exposed to air for extended periods to prevent contamination or drying.
  • Do not store the glass electrode in distilled or deionized water for prolonged periods, as this may cause ions to leak from the electrode bulb or reference solution, reducing response speed and lifespan.
  • For long-term storage, cover the glass electrode tip with a protective cap containing saturated KCl solution to prevent drying and contamination.

‌Electrode Cleaning‌

• • Keep the glass electrode surface clean to ensure measurement accuracy.
  • Rinse with clean water if contaminants are present; avoid wiping with hands or abrasive materials to prevent surface damage.

‌Regular Inspection and Replacement‌

• • Periodically check the sensor’s cables, connectors, and electrodes for damage. Replace any faulty components immediately.
  • Electrodes typically last 6–12 months, depending on usage and environmental conditions. Replace electrodes if performance degrades or they exceed their lifespan.

‌II. Calibration of pH Sensors‌

‌Prepare Standard Solutions‌

• • Use two standard solutions (e.g., pH 4.01 and pH 9.18) for a two-point calibration. Additional solutions may be prepared to cover a wider pH range if needed.

‌Calibration Procedure‌

• • Immerse the sensor in the first standard solution. Wait for readings to stabilize, then adjust the controller’s value to match the solution’s pH.
  • Rinse and dry the sensor, then repeat the process with the second standard solution.
  • After calibration, validate accuracy using a third standard solution (e.g., pH 6.86).

‌Key Considerations‌

• • Always rinse the electrode with pure water and blot dry with lint-free paper before calibration.
  • Temperature significantly impacts calibration accuracy. Ensure the current temperature is correctly input during calibration.
  • Verify electrode stability by ensuring the difference between maximum and minimum signal values in the standard solution is ‌<1 mV‌ within one minute.

By following these maintenance and calibration guidelines, you can ensure the accuracy, reliability, and longevity of your pH sensor, improving measurement precision and operational efficiency.