The role of pH meter temperature compensation
The function of the temperature compensation function is mainly used to correct the deviation caused by the difference between the temperature of the standard sample such as standard buffer during calibration (generally 25 degrees Celsius) and the temperature of the actual sample solution.
To understand why this is done, it is first necessary to understand how a pH meter measures pH. The pH meter is based on the principle of the Nernst equation. The electromotive force of the electrode has a linear relationship with the pH value. Usually, the pH meter is calibrated with two buffers with different pH values to determine the slope of the curve. This slope is proportional to temperature.
For strong electrolyte solutions, when the solution temperature changes, the hydrogen ion concentration in the solution is approximately unchanged, that is, when the pH value of the solution remains unchanged, according to the Nernst equation, the ΔE of the solution will change linearly with the temperature T. As the temperature increases, the electromotive force of the solution will increase, and the pH meter is converted into pH value according to the detected electromotive force of the solution, so temperature compensation must be performed to offset the influence of temperature on the measurement results. This is the essence of pH meter temperature compensation.
