Ammonia and Total Kjeldahl Nitrogen

Distillation• Manual distillation is not required if comparability data on representativeeffluent samples are on file to show that this preliminary distillation step isnot necessary: however, manual distillation will be required to resolve anycontroversies. In general, the analytical method should be consultedregarding the need for distillation. If the method is not clear, the laboratorymay compare a minimum of 9 different sample matrices toevaluate the need for distillation. For each matrix, a matrix spike andmatrix spike duplicate are analyzed both with and without the distillationstep. (A total of 36 samples, assuming 9 matrices). If results arecomparable, the laboratory may dispense with the distillation step forfutureanalysis. Comparable is defined as < 20% RPD for all tested matrices).Alternatively the two populations of spike recovery percentages may becompared using a recognized statistical test.2012 MUR, Table IB, footnote 6.