VPB 112: General Veterinary Biochemistry (1+1)

PREPARATION OF BUFFER - THEORY

Buffer

• Buffers are solutions, which resist the change in pH of the solution upon addition of small amounts of a conc. acid or a base.

Buffering capacity

• It is defined as the gram equivalent weight of H⁺ required by 1 L of 1M buffer solution that will change the pH by one Unit. i.e. it reflects the efficiency of the buffer in maintaining a constant pH.
• The pH of a buffer solution can be calculated by the help of Henderson-Hasselbalch equation:

pH = pKa + log [salt/acid]

pH

• It is defined as the negative logarithm of the hydrogen ion concentration

                 pH = - log [H⁺]

pKa

• It is defined as the negative logarithm of the acid dissociation constant of a weak acid or it is that pH at which the concentration of ionized and non-ionized forms are equal.