The Dumas method starts with a combustion furnace (CF) to burn the sample, obtaining elemental compounds.
Water is removed by a first physical trap (WT1 - DriStep™), placed after the combustion, and a second chemical one (WT2). Between the two, the elemental substances pass through a reduction furnace (RF). The auto-regenerative CO2 absorbers (CO2) let pass only the elemental nitrogen that is detected by the LoGas™ innovative thermal Conductivity Detector (TCD) with no requirement for a reference gas.
The NDA 701
is controlled via PC through the intuitive DUMASoft™.
Despite the low homogeneity of the cereal samples, the results are repeatable. The combustion method, relying on the Dumas principle, for the determination of total nitrogen in cereal samples, has been included as an official alternative to the Kjeldahl method. Results have been obtained with the following calibration curve: in a range of 0 - 5 mg N with 5 measurements of EDTA standard (%N = 9.57)
Benefits of Dumas combustion method are:
- High productivity, non-stop performance
- Time-saving, few minutes required
- Moderate running costs
- Totally unsupervised, fully automated
- Omission of harsh and toxic chemicals
- Eco-friendly, low amount of residues and wastes
Several organizations working with standardization and recommendation of chemical methods have approved combustion methods for the determination of nitrogen.
Of those related to brewing, the American Society of Brewing Chemists (ASBC) has approved combustion methods for nitrogen determination in brewing grains as well as in wort and beer.