The Kjeldahl method or Kjeldahl digestion in analytical chemistry is a method for the quantitative determination of organic nitrogen in chemical substances like ammonia. The method consists of heating a substance with sulphuric acid, which decomposes the organic substance by oxidation to liberate the reduced nitrogen as ammonium sulphate. In this step potassium sulphate is added to increase the boiling point of the medium (from 337 °C to 373 °C) . Chemical decomposition of the sample is complete when the initially very dark-coloured medium has become clear and colourless.
VAPODEST® is currently the most modern and powerful analysis system on the market for nitrogen analysis using the Kjeldahl method. VAPODEST® is also ideal for the steam distillation of volatile acids, sulphur dioxide, TVB-N, ammonium, formaldehyde, phenol, alcohol, vicinal diketones or hydrogen cyanide.
The VAPODEST® series is available in different degrees of automation. From the simple smart version VAPODEST® 200 for small volumes of samples, to fully automated system VAPODEST® 50s Carousel with integrated titration and autosampler for a high sample throughput. A great VAPODEST® feature is that all models are compatible with a wide variety of Kjeldahl digestion tubes and sample reservoirs. Analysis results achieved with VAPODEST® exceed the requirements of official international standards such as EN/ISO, AOAC, EPA, ASTM, GAFTA.