Minnesota Inventors Hall of Fame


Dr. Izaak M. Kolthoff - 1985 Inductee

(1894 - 1993) Professor Emeritus Izaak Maurits Kolthoff was a world renowned analytical chemist, widely regarded as the father of modern analytical chemistry. He was the chief force in developing analytical chemistry as a modern science, as reflected by nearly 1,000 scientific papers he has published, scores of textbooks he has authored, and a 30 - volume treatise on analytical chemistry. It was the originality, insight, and timeliness rather than the mere bulk of these publications that created an international reputation for Kolthoff. The significance his prodigious output of research papers, textbooks and reference books can be summarized by quoting J..J. Lingane: "Analytical chemistry has never been served by a more original mind, nor a more prolific pen, than Kolthoff’s." He is the inventor of iodometry, the originator of potentiometry and conductometry as analytical methods and the chief scholar in the fields of amperometry and electroanalytical chemistry.

During his first chemistry course in high school he developed a keen interest in the subject. Later, his mother, making chicken soup for a special dinner, had mistakenly added sodium carbonate (baking soda) instead of sodium chloride (table salt). She was ready to give up when Kolthoff, then 15, volunteered to help. He added hydrochloric acid to the soup, bringing up its pH factor until a strip of blue litmus paper turned pink. The soup was fine, he recalls. At age 21, Kolthoff published his first paper on the then-novel concept of pH (expressing acidity or alkalinity - 7 is neutral, lower values are more acid and higher values more alkaline). The origin is from p representing German Potenz 'power' + H, the symbol for hydrogen.

In 1927 he was offered a one-year appointment as a professor and chief of the Analytical Division of the School of Chemistry of the University of Minnesota. His one year appointment became permanent and he remained at Minnesota until his nominal retirement in 1962 despite attempts by other institutions (including his alma mater, the University of Utrecht) to attract him.

His work that most directly affected the general public was in the American Synthetic Rubber Research Program. It was the foremost chemical engineering project during World War II, and created a huge synthetic rubber industry in an unbelievably short period of time. Kolthoff, whose family was devastated during Nazi occupation of the Netherlands, quickly assembled a large research group and made major contributions to the program. He and his coworkers hold several key patents related to synthetic rubber. Nearly 200,000 tons of synthetic rubber were produced in 1943 and by 1944 the production rate was at 700,000 tons. Over the years the quality of synthetic rubber and the method of constructing tires were both improved, so today we have tires that will run for 60,000 to 80,000 miles compared to tires made exclusively of natural rubber that lasted only 10,000 miles.

NOTE: These biographies have been compiled from information accompanying the nomination form submitted to the Minnesota Inventors Hall of Fame, information available on the Internet and from a variety of other sources.