A modified universal semi‐micro Kjeldahl method for the determination of nitrogen in coal and other carbonaceous materials

Abstract

Abstract A semi‐micro Kjeldahl method is described, in which for the first time an unmistakable colour indication is given of the completeness of conversion into ammonium sulphate. Instead of the usual catalysts, crystalline potassium permanganate is used as oxidant and digestion is complete in about 13 minutes; the distillation takes about 8 minutes. With only a single distillation unit, 36 determinations can easily be made in a working day. The method has been thoroughly tested in our laboratories for about six months.