Page 70 - Pharmaceutical_Analytical_Chemistry_1_Theoretical_Notes_Level_1

Mansoura National University
Pharm D-Clinical Pharmacy Program Level 1 Pharm. Anal. Chem. 1 (PC 101)

What is a Buffer Solution?
• The buffer is a solution which resists changes in pH upon addition of a small

amount of a strong acid or a strong base.

Types of Buffer:

• Consist of a weak acid and its salt.
1) Acidic Buffers
• [e.g. acetic acid and sodium acetate (acetate buffer)]

• Consist of a weak base and its salt.
2) Basic Buffers
• [e.g. amm. hydroxide and amm. chloride (ammonia buffer)]

The effect of adding acid or base to an unbuffered solution:

The effect of adding acid or base to a buffered solution:

Acidic Buffers

• The most common acidic buffers used are acetate, borate, citrate, phosphate

and phthalate buffers.

• Example: mixture of acetic acid and sodium acetate:

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