What conclusions can be drawn from the titration curves of amino acids?
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Solution
Titration of amino acid:
Amino acids consist of an amino acid group and an acidic carboxyl group.
When an amino acid is dissolved in water, it mostly takes on the isoelectric form; but, when titrated with an acid, it behaves as a base and when titrated with a base, it behaves as an acid (a substance that can behave as either an acid or a base is known as an amphoteric compound).
When successive additions of acid or alkali cause the pH of a given volume of a sample solution to change, titration curves are produced. The curves are typically graphs of pH vs volume of titrant added.
Observations of titration of an amino acid (glycine):
From the amino acid titration curve, we can learn important details regarding amino acids, such as pKa and pI, additionally, it gives details regarding the examined amino acid's buffering range, The number of dissociable protons can be calculated from the number of plateaus on a titration curve.
Both groups are totally protonated when the solution contains a very low pH (acidic).
The group begins to be deprotonated as the pH rises.
When pH equals pKa1, it will serve as a buffer and the mixture will have an identical amount of
As the pH rises further, the majority of the solution's ions will be zwitter ions, and at this point, the pH is equal to pI(It is the average value of pka if both carboxyl and aminoacid group.).
The second group, , will deprotonate as the pH rises.
After that, the solution will have an equal amount of each of the following when , acting as a buffer:
