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Stability of solutions

  1. Sep 30, 2016 #1

    asy

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    Hello everyone,

    I need to know the stability and storage conditions of some solutions that I need to prepare. Is there a place where I can find this information (at least for most common solutions)? Or is there any bibliography to consult?

    Thanks
     
  2. jcsd
  3. Sep 30, 2016 #2

    Bystander

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    Google "reagent stability."
     
  4. Sep 30, 2016 #3

    asy

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    :p

    thanks... but... Not always that easy!
     
  5. Sep 30, 2016 #4

    Bystander

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    Organic? Inorganic? Redox? Acid-base?
     
  6. Sep 30, 2016 #5

    asy

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    I will need to make the following for determining enzyme activity.

    0.1 M Hydroxylamine; 10 mM Glutathione; 30 mM CBZ-L-glutaminylglycine

    and I am trying to find out if I can make this a stock solution or if I have to make it fresh every time.


    Thank you
     
  7. Oct 1, 2016 #6
    You can probably get away with a stock solution. Use amber volumetrics, and store in a refrigerator. Allow to warm to room temp before taking alliquots. You can always store under a blanket of nitrogen as well.
     
  8. Oct 1, 2016 #7

    jim mcnamara

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    @Kevin McHugh
    Abcam recommends for reduced glutathione: fresh solutions are best but store in an air tight vial, one week max:
    www.abcam.com/Reduced-Glutathione-GSH-ab142044.pdf

    I would suggest that a single storage approach might not be appropriate for everything.
     
  9. Oct 1, 2016 #8
    Yeah, bio reagents are little different than the reagents I've commonly used. Thanks Jim.
     
  10. Oct 2, 2016 #9

    epenguin

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    I had slightly looked into that, thinking that you might have come back after my last related post. :frown:

    I think I would, as others have recommended, make up the solutions, all the components mixed, enough for a weeks work and only change if it seems you're getting different results from one day to another. I would make up the solution containing the requisite moles of your three substances to about three quarters of the required volume, Bring to pH as said by Borek with acid or alkali, and then bring to 100% volume. Keep this stock in the fridge.

    Hydroxylamine is sold as a 50% solution, and also as the hydrochloride salt and sulphate. Off the top of my head I would normally expect the salts to be more stable. But they are hygroscopic so I think they should be stocked in a desiccator, cold. Often you get some information from vendors' catalogues, and other stuff I give below for what it is worth. At any rate you will note that this stuff is classified as mildly hazardous, but just normal precautions should be okay.

    For which of the sources and what form of the stuff to prefer, in the scientific publications of the other people working on your system the sources will often be stated in the 'Materials and methods' of their papers.

    https://pubchem.ncbi.nlm.nih.gov/compound/hydroxylamine#section=Auto-Ignition
    http://www.sigmaaldrich.com/catalog/search?term=Hydroxylamine&interface=All&N=0&mode=match partialmax&lang=it&region=IT&focus=product
    https://pubchem.ncbi.nlm.nih.gov/compound/Hydroxylamine_hydrochloride#section=Decomposition
    http://www.labchem.com/tools/msds/msds/LC15515.pdf
    http://www.sigmaaldrich.com/catalog...=it&region=IT&gclid=CMuUroC3vM8CFS8o0wodYRYMn
     
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