Main Entry: Hen·der·son–Has·sel·balch equation

Pronunciation: \ˈhen-dər-sən-ˈhas-əl-ˌbälk-\

Function: noun

: an equation that equates the pH of a buffered solution (as the blood) to the sum of the cologarithm (p) of the dissociation constant (K) of the acid in the buffer and the logarithm of the ratio of the concentration ([ ]) of the salt to that of the acid and that is written

Henderson, Lawrence Joseph (1878–1942), American biochemist. Henderson is remembered for his discovery of the chemical means by which acid-base equilibria are maintained in nature. In his investigations of body fluids, he discovered that the formation of carbonic acid from carbon dioxide and water in the presence of the salt of the acid (bicarbonates) is the only system in nature that maintains acid-base equilibrium. Henderson developed a chemical equation used to describe these systems, known as physiological buffers. This equation is of fundamental importance to biochemistry.

Hasselbalch, Karl Albert (1874–1962), Danish biochemist. In 1916 Hasselbalch converted the equation developed by Lawrence Henderson into logarithmic form. Although the Henderson-Hasselbalch equation is only approximately true, it still remains the most useful mathematical model for treating problems dealing with buffer solutions.