Does the benchmark reagent anhydrous sodium carbonate have a shelf life?
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Dear teachers, I have a question, does the benchmark reagent anhydrous sodium carbonate have a shelf life? The two-year-old benchmark reagent obviously deviated from the normal value when used.
benchmark reagent: anhydrous sodium carbonate * * Standard GB1255-90 does not mention the shelf life. See link: http://news.chemnet.com/item/2011-03-15/1514392.html
Reference reagents are generally very chemically stable substances and will not deteriorate during use unless they are contaminated. Moreover, sodium carbonate is used as an alkaline standard material, and it requires drying before using the amine, so it should be reliable. What does the author mean by deviation from normal value? List the data and explain how you obtained the data that you think is a deviation.
It may be that there is no constant dry weight....it contains water!
You can purchase another manufacturer's benchmark reagent. The ones we use here are from Tianjin Comeo, which have no shelf life.
There is no shelf life, but the standard does not recommend it to exceed 2 months. It is best to configure a new one, which is not troublesome.
There is no shelf life. It is estimated that the drying time and temperature are not correct.
The benchmark materials are all stable and will not deteriorate after long-term storage.
A bottle of potassium hydrogen phthalate from 2009 was used to calibrate 1 mol/L sodium hydroxide, and the obtained data was 1.0055. During production, the titration of hydrochloric acid and sulfuric acid showed abnormality. For 98% concentrated sulfuric acid, the titrated data was 94.5%. I bought a new bottle of phthalate and used it. The original 1.0055 mol/L sodium hydroxide concentration was 1.2000 mol/L. . . . .