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  • Making a phosphate buffer

    Posted by Nikifarokhi on September 19, 2021 at 6:10 am

    Hi guys
    I have a sample of disodium hydrogen phosphate. Unfortunately, I do not have its conjugated acid, which is sodium dihydrogen phosphate. Could you please advise me how can make a buffer to maintain the pH at 6.8? 
    Is it possible to use phosphoric acid to create the conjugated acid in situ (I mean using a little phosphoric acid that can completely react with the extra amount of disodium hydrogen phosphate to produce sodium dihydrogen phosphate by means of which the pH of a solution could buffer at pH 6.8)? if so, how can I calculate that?

    or is it possible to use another weak acid like citric acid with disodium hydrogen phosphate to create a buffer for pH 6.8?
     

    pharma replied 2 years, 6 months ago 2 Members · 1 Reply
  • 1 Reply
  • pharma

    Member
    September 19, 2021 at 11:55 am
    You can use phosphoric acid. It is possible to estimate by calculation though using a table is easier. In the end, you’d have to manually adjust anyways.
    You can also use citric acid instead.

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