This European Standard specifies the determination of Kjeldahl nitrogen according to the Kjeldahl procedure in sludge, treated biowaste and soil. Nitrate and nitrite are not included. Compounds with nitrogen bound in N-N, N-O linkages and some heterocycles (pyridines) are only partially determined. The limit of detection (LOD) is usually 0,03 % nitrogen, and the limit of quantification (LOQ) is 0,1 % nitrogen (using 0,25 mol/l sulfuric acid for titration).