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Lidstrom:Buffers: Difference between revisions
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=== How does temperature affect the pH of a buffer? === | === How does temperature affect the pH of a buffer? === | ||
Amine-containing buffers are most sensitive to changes in temperature. Example: Tris-HCl adjusted to pH=8.0 at 25°C will have a pH of 8.78 at 0°C. | * (source: [http://www.amazon.com/Enzyme-Assays-Practical-Approach-Series/dp/0199631425/ref=sr_1_1?ie=UTF8&qid=1383921457&sr=8-1&keywords=0199631425 ISBN 0-19-963142-5] pg 319) | ||
** Amine-containing buffers are most sensitive to changes in temperature. Example: Tris-HCl adjusted to pH=8.0 at 25°C will have a pH of 8.78 at 0°C. | |||
Carboxylic acid buffers are least sensitive to changes in temperature. Example: acetate buffer adjusted to pH 4.5 at 25°C will have a pH of 4.495 at 0°C. | ** Carboxylic acid buffers are least sensitive to changes in temperature. Example: acetate buffer adjusted to pH 4.5 at 25°C will have a pH of 4.495 at 0°C. | ||
** '''These differences are due to the differences in ΔH for ionization of the acids.''' | |||
'''These differences are due to the differences in ΔH for ionization of the acids.''' | * [http://www.applichem.com/fileadmin/Broschueren/BioBuffer.pdf Applichem publication] | ||
** The pH value of a Tris solution set to a pH of 7.8 at room temperature is 8.4 at 0°C and 7.4 at 37°C. | |||
=== How do method developer chose between sodium and potassium phospahte buffers? === | === How do method developer chose between sodium and potassium phospahte buffers? === | ||
