The pH standard buffer has the following characteristics:
(1) The pH value of the standard solution is known and reaches the specified accuracy;
(2) The pH value of the standard solution has good reproducibility and stability, with a larger buffer capacity, smaller dilution value, and smaller temperature coefficient;
(3) The preparation method of the solution is simple;
How to prepare a pH standard buffer solution?
For general pH measurement, a complete set of pH composition reagents (capable of preparing 250mL) can be used. When preparing the solution, deionized water should be used and pre boiled for 15-30 minutes to remove dissolved carbon dioxide. Cut open the plastic bag and pour the reagent into a beaker. Dissolve it with an appropriate amount of deionized water, rinse the packaging bag, and then pour it into a 250mL volumetric flask. Dilute to the mark and shake well.
3. How to properly store and use pH buffer solutions?
After preparing the buffer solution, it should be packed in a glass or polyethylene bottle (alkaline pH buffer solution, such as pH=9.18, pH=10.01, pH=12.46, etc., should be packed in a polyethylene bottle) with a tight lid. It should be stored in a refrigerator at low temperature (5-10 ℃) and can generally be used for about six months. If there is turbidity, mold, or precipitation in the existing mixer, it cannot be used again. When using, several 50mL polyethylene small bottles should be prepared, and the component solution from the large bottle should be poured into the small bottles. The bottles should be left at ambient temperature for 1-2 hours, and the temperature should be balanced before use. After use, it is not allowed to pour it into a large bottle to avoid contamination. The buffer solution in the bottle can be used for 2-3 days under environmental conditions>10 ℃. Generally, pH=7.00, pH=6.86, and pH=14.00 can be used for a longer time. pH=9.18 and pH=10.01 solutions absorb carbon dioxide in the air, and their pH value is relatively easy to change.
