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- Posts: 6
- Joined: Wed Jul 31, 2013 12:37 pm
I post this message because i have a question about standard stock solution used to therapeutic drug monitoring by LC-MS/MS.
In our laboratory, we use standards in ampulla, generally with one molecule solubilised in methanol at 1 mg/ml with a final volume of 1 ml. After opening, the solution is transferred into amber glass with teflon cap, and stored at freezer.
I have a problem because i suspect methanol evaporation of my standard solution leading to higher concentration that expected.
I would like to know if somebody has already noticed the same problem in its laboratory ? Or eventually if somebody has suggestions or advices to solve my problem ?
Thank you in advance.