Determination of Nitrogen as Elementary N, an Alternative to Kjeldahl

Abstract

LECO FP-228 N-determinator has been tested and nitrogen contents in samples of both animal and plant origin have been measured. The results were compared to nitrogen contents obtained by Kjeldahl determinations (Kjel-foss). Reproducibility and repeatability were excellent in FP-228 (within 2%) except in samples like maize, hay, corn silage and maize silage. Good agreement was found between the two methods when analysing feeding stuff, barley, wheat, oat, soy bean, bonemeal, fishmeal, pea, molasse, chicken and lamb. Analyses of maize, hay, grass, straw, grass silage, maize silage, sugar beet and potato resulted in greater differences (>5%), FP-228 with the highest results. The differences might be explained by nitrate in a few of the samples tested, but in the other samples tested there were no obvious explanations.