Practical Limitations in the use of Buffers

Abstract

The suitability of a buffer system for any particular application depends on many factors, the first of which is the pK_a value of the buffer acid or base. For a buffer to be effective, its pH must be within the range pK_a ± 1, or preferably, within pK_a ± 0.5. The former scarcity of buffer substances with a pH range 6 to 8 frequently led to the use of buffers such as phosphate or Tris in pH regions where they had little buffer capacity.