Buffer

2018-12-08T14:12:48Z

180083606:

By definition, a buffer is a substance (usually a weak acid and its conjugate base) which is added to a sample to avoid changes in its ph. An example of a buffer would be an amino acid as it has a carboxyl group and an amine group. The name for this type of buffer with both a positive ion and negative ion in its molecule is called a zwitterion. A buffer must contain the chemical species for “neutralizing” added amounts of [[Acid|acid]] or [[Base|base]]. For example, if a buffer was a solution of a [[Weak acid|weak acid]] and its conjugate [[Base|base]] it would contain [[Acetic acid|acetic acid]] and [[Sodium acetate|sodium acetate]] or a [[Weak base|weak base]] and conjugate acid it would contain [[Ammonia|ammonia]] and [[Ammonium chloride|ammonium chloride]]. If there is a lot of acid or alkali added then the buffer will not be able to cope with such a change and will no longer able to maintain the pH.

Within the body, there are three major buffer systems; the carbonic acid bicarbonate buffer system, phosphate buffer system and the protein buffer system.

Buffers are most effective in the range [[PH]] = pK’a ± 1. Outside the range the [[Concentration|concentration]] of either the [[Acid|acid]] or the conjugate [[Base|base]] is too small to effectively resist the effect of added [[Hydrogen|hydrogen]] or [[Hydroxide|hydroxide]] [[Ion|ions]].

== '''Examples of buffers that are found in the blood<ref>Lawrie Ryan and Roger Norris. Cambridge International AS and A Level Chemistry Coursebook. 2nd ed. In: Chapter 21: Further aspects of equilibria, page 315. United Kingdom: University Printing House, Cambridge CB2 8BS.</ref>''' ==

*Hydrogencarbonate ions, HCO3-  
*Haemoglobin and plasma proteins
*Dihydrogenphosphate (H2PO4-) and hydrogenphosphate (HPO42-) ion.

=== References ===

<references />

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Buffer