What are pH electrode storage solution and pH 7.0 buffer and for what are they used?

Answer 1

The buffer solution is used to calibrate the meter. Usually two buffer solutions are used to do this. One is close to the range of the sample that will be measured, like the 7.0 buffer that you mention could be used for aquarium water. The other solution would be more acidic, like a 4.0 buffer solution. The process is to calibrate in one solution, rinse the probe, then calibrate in the other solution. This back and forth is done until the meter is reading the desired buffer and is stable. In other words, you would finish with the 7.0 buffer solution when it is reading exactly 7.0 PH, with no further adjustments after switching from the 4.0 solution. The probe should be rinsed with PH neutral DI water and shaken dry between each between each measurement so that solutions are not mixed. The storage solution is used to store the glass probe for long periods of time. A few drops of storage solution should be dripped into the probe cap before replacing it for storage. The storage solution is just a buffer that has some anti-bacterial additives to keep stuff from growing in it. The calibration buffer can be used for short term storage though. The glass probe should NEVER be allowed to dry out for long periods and should be rinsed with DI water before storage. It should NOT be stored in DI water though. Only buffer solution or storage solution should be used.