The Development and Application of the Kjeldahl Process for Legislative Purposes

the Kjeldahl Process for Legislative Purposes R. S. H.qrruI-r Ridge House, Ridgeway Close, Hyde Lea, Stafford ST18 gBE Based on a paper given at a meeting of the North West Region ofthe Analytical Division of The Royal Society of Chemistry, Bolton Institute of Higher Education, 23 February 1983, on the occasion of the Centenary of the first publication of the process. This discussion of the development and application of the Kjeldahl process for the determination of Nitrogen in organic materials is confined to that which can be traced through the course of legislation in the United Kingdom, but which has been influenced by the work of the Association of Official Analytical Chemists (AOAC) in the U.S.A. various EEC Committees and the International Standards Organisation (ISO). The historical aspects have been discussed by Morriesl. Kjeldahl’s discovery that organically combined nitrogen was converted to ammonia by digestion with sulphuric acid2 is of fundamental importance to the science of food and agriculture, but while there has been built up over the 100 years a great mass of nutritional data dependent upon the accurate determination of protein nitrogen, the use of the Kjeldahl