Karl Albert Hasselbalch

Karl Albert Hasselbalch ([ˈkɑːˀl ˈalˀbɐd ˈhasl̩balˀɡ]; 1 November 1874 in Aastrup, Denmark – 19 September 1962) was a physician and chemist. He was a pioneer in the use of pH measurement in medicine (with Christian Bohr, father of Niels Bohr), and he described how the affinity of blood for oxygen was dependent on the concentration of carbon dioxide. He was also first to determine the pH of blood. In 1916, he converted the 1908 equation of Lawrence Joseph Henderson to logarithmic form, which is now known as the Henderson–Hasselbalch equation.