Key Factors Affecting pH Electrode Measurement Accuracy

As a core component for detecting the acidity and alkalinity of solutions, the measurement accuracy of a pH electrode directly impacts the reliability of experimental analysis, industrial process control, and water quality monitoring. Understanding and controlling the key factors affecting pH electrode accuracy is crucial to ensuring the accuracy of measurement data.

Temperature is one of the most important factors affecting pH measurement accuracy. The potential response of a pH electrode shifts with temperature changes. Without temperature compensation or manual correction, measurement results often become inaccurate. Therefore, in high-precision applications, a pH electrode with automatic temperature compensation (ATC) should be selected, and the sample temperature should be kept stable.

The condition of the electrode itself directly affects accuracy. Aging, contamination, or damage to the electrode's sensitive membrane can lead to slowed response speed and zero-point drift. Especially when measuring samples containing oils, organic solvents, or high salinity, the electrode surface is easily covered with a contaminant layer, affecting ion exchange performance. Therefore, regular electrode cleaning, proper storage, and avoiding drying are essential for maintaining accuracy.

The stability of the reference electrolyte and liquid junction is also crucial. If the liquid junction of the reference electrode is blocked or the electrolyte concentration changes, the internal potential of the electrode will fluctuate, affecting the repeatability and stability of the readings. It is recommended to use a replenishable reference solution and replace it regularly to ensure smooth ion flow.

The calibration method and the quality of the calibration solution are also crucial to measurement accuracy. Using expired or contaminated standard buffer solutions can lead to calibration deviations, affecting subsequent measurement results. It is recommended to calibrate the electrode regularly according to usage frequency and to use high-quality, precisely prepared buffer solutions.

The main factors affecting the accuracy of pH Electrode measurements include temperature variations, electrode condition, reference system stability, and calibration operation procedures. Scientific maintenance and correct use can effectively improve the accuracy and repeatability of pH measurements, ensuring the reliability of test results.