How to properly store and use pH buffer solutions?
After preparing the buffer solution, it should be placed in a glass bottle or a polyethylene bottle (alkaline pH buffer solutions such as pH 9.18, pH 10.01, pH 12.46, etc. should be placed in polyethylene bottles). The bottle cap should be tightly closed and stored at low temperature (5-10 ℃) in the refrigerator. It can generally be used for about six months. If turbidity, mold or precipitation are found, it cannot be continued to be used. When using, prepare several 50mL polyethylene small bottles, pour the buffer solution from the large bottles into the small bottles, and let them stand at ambient temperature for 1-2 hours until the temperature is balanced before use. After use, it should not be poured into the large bottle to avoid contamination. The buffer solution in the bottle can be used for 2-3 days under environmental conditions of>10 ℃. Generally, the pH 7.00, pH 6.86, and pH 14.00 solutions can be used for longer periods of time. pH 9.18 and pH 10.01 solutions are prone to pH changes due to the absorption of carbon dioxide from the air.
What is the purpose of pH buffer solution?
Calibrate the pH meter before measuring pH.
To verify the accuracy of a pH meter, for example, after calibrating the pH meter with pH 6.86 and pH 14.00, insert the pH electrode into the pH 9.18 solution and check whether the instrument display value is consistent with the pH value of the standard solution.
Is it necessary to recalibrate the pH meter during general precision measurement. After calibrating and using the pH meter, drift or changes may occur. Therefore, before testing, insert the electrode into a standard buffer solution that is close to the measured solution, and determine whether recalibration is necessary based on the magnitude of the error.
