pH electrode calibration

pH correction is often performed using the "two-point method".

Configure a set of saturated pH buffer solvents in advance

It is recommended to use standard solutions with pH values ​​of 4.01 and 6.86 for pH electrodes commonly used to measure acidic medium environments

It is recommended to use standard solutions with pH values ​​of 9.21 and 6.86 for pH electrodes commonly used in measuring alkaline medium environments

pH=6.86 is the zero point, under normal circumstances, the zero point should be corrected first.

The electrode can be soaked in acidic buffer (pH4.00) for several minutes before use, and then soaked in neutral buffer (pH6.86 or 7.00, etc.) for several minutes. Then start the calibration again. (For the Mettler pH electrode, use the knife attached to the electrode to carefully scrape off the silica gel before use. The direction should be from front to back to avoid scratching the sensitive membrane. Note that all the silica gel on the diaphragm should be scraped off until the tip of the knife touches porous ceramics on the diaphragm). Take buffer solutions with pH values ​​of 4.01 and 6.86 as an example. First put the pH electrode into the buffer solvent of PH=6.86, after the signal value is stable, enter "6.86" ​​in the "Standard Value 1" box, click OK to correct, then take it out, rinse the solution remaining on the electrode with distilled water, Blot the water with paper (please do not wipe the electrode with a paper towel to avoid electrostatic interference), put it in a buffer solvent with pH=4, and after the signal value is stable, enter "4" in the "Standard Value 2" box and click OK to calibrate , then take out the solution remaining on the electrode and rinse it with distilled water, blot the water with paper (do not wipe it), and ferment it for later use.

Clean the electrodes after fermentation and use, and store them in saturated potassium chloride solution.