PH measurement

From Molecular Biology Wiki

pH Measurement

In order to measure the pH, you need either a pH indicator or a pH meter of which the pH meter is usually more accurate (especially if you buy a good one).

pH Meters

pH Measurement Tips

To measure the pH, make sure you have the pH electrode in a vertical position.

• Gently stir the buffer solution when adjusting the pH.

• Never put the electrode in solutions containing SDS.

• Periodically calibrate the electrode with at least two calibration solutions.

• Store the pH electrode in solution, keep the diaphragm wet and make sure that there is always electrolyte solution inside the electrode.

• Wash clean the pH electrode with distilled water after usage and carefully tamp the electrode with cleaning paper.

• Caution: the pH of most solutions is temperature-dependent:

At 5°C the pH of a 0.05 M Tris solution is 8.07 At 25°C the pH of a 0.05 M Tris solution is 7.50 At 37°C the pH of a 0.05 M Tris solution is 7.22