This is an instructional video on how to calibrate, store and use a pH meter. The following are important facts to keep in mind regarding calibration. It is important to calibrate often when high accuracy is required for measurements.

It is also important to calibrate at least once a week after having tested aggressive chemicals or for example when the pH electrode is replaced. A minimum of a two-point calibration using the standard buffers provided by the manufacturer is required. It is possible to conduct up to a five-point calibration but this depends on the type of pH meter you are using and the experiment to be conducted.

The type of standard buffer determines how long it can be used after being opened. This information can be obtained by referring to the manual or by directly consulting the manufacturer. Important to keep in mind is also the process of storing the pH meter.

The electrode should not be allowed to dry out. This is prevented by storing the electrode in storage solution which is found in the protective cap. Keep in mind that you should never store the electrode using distilled or deionized water. Again for detailed information on how to proceed otherwise, refer to the manual or directly consult the manufacturer.

The following are all the materials, chemicals and instruments used for the experiment. The standard pH buffers are transferred from the original packaging to 50 milliliter falcon tubes together with a magnetic rod for each tube. In addition to the pH meter, the electrode and the protective cap of which are

labeled, a magnetic stirrer, distilled water and a clean beaker to collect the waste are used. The instruction manual is kept nearby and referred to whenever needed. Now let's proceed with the experiment.

Begin by switching on the instrument using the on-off button. Next, remove the cap of the electrode. The prior contains a storage solution which maintains electrode hydration during storage. Wash the electrode thoroughly using distilled water and a clean beaker to collect the waste.

Using a clean paper towel, wipe off any excess liquid and don't forget to loosen the electrode wheel before measuring. To begin calibration, measure the pH of 4.01.

Place the falcon tube consisting of both the solution and magnetic rod on a magnetic stirrer. This allows for equal distribution during measurements. Immerse the electrode in the solution but make sure it is not in contact with the magnetic rod as this might damage the electrode.

Since this is the first step of calibration, press CAL and then CLEAR to remove any prior measurements. Observe the drop in pH and wait for the status table to pop up on the screen. After achieving stability, press ACCEPT and wait for the pH meter to confirm calibration.

After having done so, proceed with the next measurement with a different pH level. Remove the electrode from the falcon tube to continue with the next step of calibration. Before switching any solutions, remember to wash the electrode as described before, again using distilled water and a clean beaker to collect the waste.

Don't forget to remove the excess liquid using a clean paper towel. A pH of 7.01 will be measured. Place a falcon tube consisting of the solution and the magnetic rod onto the magnetic stirrer.

Immerse the electrode into the liquid while avoiding contact with the magnetic rod. This time, an increase in pH is observed. Wait for the status table to be obtained. After achieving stability, press ACCEPT and wait for the pH meter to confirm calibration.

After having done so, proceed with the last measurement of the calibration. As before, remove the electrode from the solution and wash with distilled water.

Remove any excess liquid and prepare the solution with a pH of 10.01. Place the falcon tube consisting of the solution and a magnetic rod onto the magnetic stirrer. Immerse the electrode in the solution.

After the pH meter is stabilized, press ACCEPT and wait for the confirmation of calibration. Since this is the last step of calibration, press ESC and remove the electrode from the solution.

Wash as described before prior to any further measurements. The pH meter can now either be used for further measurements or be stored.

If the pH meter is no longer being used, store the electrode by placing the cap back on and tighten the wheel gently.

If you want to measure a buffer of your choice, prepare the pH meter by removing the cap of the electrode, loosening the wheel and washing thoroughly with distilled water.

The buffer to be measured is transferred to a clean beaker together with a magnetic rod. The electrode is immersed into the buffer deep enough to achieve accurate results while maintaining an appropriate distance with a magnetic rod. After achieving the desired pH, which in this case is 7.47, remove the electrode from the buffer.

Wash one last time before either using it for further measurements or storing. To store, place the cap back on, tighten the wheel and don't forget to turn the instrument off.

This way, you have managed to correctly calibrate the pH meter and also measure the pH of your buffer.