How to Calibrate a pH Meter

oakton benchtop meter with probes and nist traceable ph buffers

What is a pH meter?

A pH meter measures the alkalinity and acidity in a solution that can be critical to many laboratory, environmental, chemical, and processing applications. Whether you are performing pH testing in the lab or field, you can find a variety of testers and meters to meet your needs. Pocket-sized testers are an economical alternative for routine measurements. Handheld portable meters are ideal for field, manufacturing floor, and lab. Benchtop meters are the choice for high-accuracy pH measurements on the lab bench. Specialty pH/mV meters plus ISE electrodes and ISFET electrodes handle specific ion applications or harsh environments.

Before you calibrate

Condition your pH tester electrode by immersing it in electrode storage solutionpH 4 buffer, or tap water for at least 30 minutes before use. Do not use deionized water.

When to calibrate a pH meter

Calibrate your pH meter prior to each use or at least one time per four hours of use. Calibration corrects for inconsistencies inherent in all electrodes, particularly as they age or become contaminated. To calibrate a pH meter, you should refer to your specific pH meter’s manual. Each meter may be a little different but the calibration steps are similar.

How to calibrate a pH meter or pH tester

Here is a basic instructions on how to calibrate a pH meter for one-point calibration. Refer to your tester or meter’s manufacturer’s user manual for step-by-step instructions on exact calibration or one-, two- and three-point calibration.

1- Turn on your meter. Press the on/off button for a few seconds to turn on the tester or meter.

2- Prepare your buffer solution. You will generally need more than one buffer for calibrating a pH meter if you are performing more than a one-point calibration. For one-point calibration, use a pH 7.0 buffer solution. To prevent contamination, do not dip your electrode into the bottle, discard the buffer after use, and do not pour the buffer back into the bottle.

3- Take the pH meter electrode from its storage solution and rinse with distilled water. Do not touch it or touch the electrode against anything.

4- Dip the clean electrode into the pH buffer solution. Press the calibrate button and wait for the meter to stabilize. Remove the electrode from the buffer solution. Rinse the electrode again with distilled water.

You are ready to test the pH of your solution.

Need a pH meter?

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