Johan Kjeldahl

Professional life

Kjeldahl worked in Copenhagen at the Carlsberg Laboratory, associated with Carlsberg Brewery, where he was head of the Chemistry department from 1876 to 1900.

Role in analytical chemistry

Background

  He was given the job to determine the amount of protein in the grain used in the malt industry. Less biochemistry at the time were far from accurate.

Kjeldahl method

Main article: Kjeldahl method

In order to solve the problem of determining nitrogen content in a sample, Kjeldahl developed a method which involves a two-step reaction: a caustic soda to indirectly measure nitrogen.

During the 1880s, Kjeldahl used buffer solution.

On March 7, 1883, Kjeldahl presented his method at the Danish Chemical Society.  

Legacy

Johan Kjeldahl died on July 18, 1900 in Copenhagen, Denmark at the age of 50.

His laboratory technique for nitrogen and protein analysis is still the universally accepted method for this analysis. Although other methods claim to be faster and more efficient, none can cope with the variety of sizes or conditions of samples than Johan Kjeldahl's original method. Kjeldahl equipment is used extensively all over the world.

Literature

• Jessen-Hansen, H. (1932) Johan Kjeldahl, pp. 169-172 in: Meisen, V. Prominent Danish Scientists through the Ages. University Library of Copenhagen 450th Anniversary. Levin & Munksgaard, Copenhagen.