What is commonly done to ensure accurate pH readings before use?

Calibration of the meter is essential to ensure accurate pH readings before it is used. This process involves adjusting the meter to account for any deviations in its readings due to factors such as age, storage conditions, or previous use. Calibration typically involves using standard buffer solutions with known pH values, which helps to establish a relationship between the meter’s output and the actual pH of the buffers. This ensures that measurements taken later will be reliable and reflect the true pH of the samples being tested.

While soaking the electrode, cleaning the probe, and testing with known solutions are important practices in maintaining pH meters, they serve different purposes. Soaking the electrode is primarily done to rehydrate it when it has been dry, but it doesn't necessarily ensure accuracy. Cleaning the probe is important for removing any build-up or contaminants that could affect readings, yet it too does not calibrate the meter. Testing with known solutions, while useful for verification, is not a substitute for the systematic calibration process that adjusts the meter's settings based on standard buffers. Thus, calibration is the fundamental step to achieve and maintain accurate pH measurements.