McIlvaine buffer is a

buffer solution A buffer solution is a solution where the pH does not change significantly on dilution or if an acid or base is added at constant temperature. Its pH changes very little when a small amount of strong acid or base is added to it. Buffer solution ...

composed of

citric acid Citric acid is an organic compound with the formula . It is a Transparency and translucency, colorless Weak acid, weak organic acid. It occurs naturally in Citrus, citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, ...

and

disodium hydrogen phosphate Disodium phosphate (DSP), or disodium hydrogen phosphate, or sodium phosphate dibasic, is an inorganic compound with the chemical formula . It is one of several sodium phosphates. The salt is known in anhydrous form as well as hydrates , where ' ...

, also known as citrate-phosphate buffer. It was introduced in 1921 by the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

agronomist Theodore Clinton McIlvaine (1875–1959) from

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, and it can be prepared in pH 2.2 to 8 by mixing two stock solutions.

Applications

McIlvaine buffer can be used to prepare a water-soluble mounting medium when mixed 1:1 with glycerol.

Preparation of McIlvaine buffer requires

disodium phosphate Disodium phosphate (DSP), or disodium hydrogen phosphate, or sodium phosphate dibasic, is an inorganic compound with the chemical formula . It is one of several sodium phosphates. The salt is known in anhydrous form as well as hydrates , where ...

and

. One liter of 0.2M stock solution of disodium hydrogen phosphate can be prepared by dissolving 28.38g of disodium phosphate in water, and adding a quantity of water sufficient to make one liter. One liter of 0.1M stock solution of citric acid can be prepared by dissolving 19.21g of citric acid in water, and adding a quantity of water sufficient to make one liter. From these stock solutions, McIlvaine buffer can be prepared in accordance with the following table:

References

{{Reflist Liquids Biochemistry Buffer solutions

Applications

Contents

References