We found few chemicals in powder form and liquid form which the date written was ~10 years back . From the knowledge , it is still being acceptable if it is 5 years back. However, 10 years are too long and it still looks good. Hope someone can assist to verify this. Thank you !
It depends on which chemical it is and for what purpose it should be used. If it is an analytical standard for some compound that is known to be unstable, it might not be a good idea to use it. Other situations might be less critical.
One cannot give a general answer to your question because there are vast differences in the stability of chemicals. And, of course, it depends on the conditions (temperature, exclusion of air and/or humidity) under which the chemicals have been stored. I would try chromatographic methods (TLC, HPLC, GC) to check whether the chemical in question consists of a single compound and spectroscopic methods (in particular NMR, but also MS and IR) to check the identity of the compound. If everything is in good order and the chemicals are not for human consumption, I see no reason not to use the substance, e. g. as a starting material for a chemical reaction, no matter how old it is.
Just try it.
Best regards
Nobody can give a specific answer unless you provide specific details.
In general, for quantities of chemicals likely to be in most laboratories, the cost of verifying the purity of a questionable batch is higher than the value of the chemicals.
Thank you for the answers, everyone! Fortunately, superior decided to buy new chemicals. The current chemicals will be discarded in proper way.
You can go for validation of your chemicals if validation data comes in limit you can use your chemicals.
The main risks are always oxidation and hydration or hydrolysis. Therefore, whatever the delay will be, it is better to keep the chemicals in a dry, cool place. Obviously, it also depends whether the package or bottle is tightly closed or has been opened. Clogging and discoloration are bad signs.
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