Nitrogen determination in fertilizer

Reference methods:
AOAC 993.13
DIN EN 13654-2



Importance of fertilizer in agriculture

Modern agriculture has increasingly developed into an essential economic sector worldwide. As in many other industrial sectors, the efficient use of all available ressources is becoming more an more important. One of the major raw materials is the fertilizer, as an essential factor for the plant growth. The ideal content of nutrients plays a particularly important role here. Regardless of wether mixed fertilizers or special fertilizers such as nitrogen fertilizers, in order to guarantee optimum plant growth and not unnecessarily pollute the environment, the amount of nutrients must be perfect. One of the main nutrients in fertilizers is nitrogen, which can be determined either by the method acc. to Kjeldahl or the method acc. to Dumas.

Determination of nitrogen contents in fertilizers with DUMATHERM

Due to the short time needed for the analysis, the nitrogen determination acc. to Dumas with corresponding automatic analyzers is particularly suitable for laboratories and quality management of large industrial companies with a very high sample volume. By using the DUMATHERM from C. Gerhardt, the result is already available after approx. 3 minutes. However, the acidic solutions / vapours resulting from the combustion of the sample are a significant restriction when determining the nitrogen content of fertilizers with common automatic analyzers. Connecting components made of metal are generally used in analytical instruments. These components can corrode after a certain period of time, causing leaks and leakage of gases used during the analysis. This leads to high failure rates and considerable costs for laboratories and can, in the worst case, be a significant safety issue. The DUMATHERM from C. Gerhardt has been adapted to the special requirements of customers in the fertilizer industry and uses elements made of chemical-resistant materials instead of metal connectors in order to guarantee a low failure rate even at high throughput rates. Another advantage over competing products is the use of environmentally friendly consumables, such as the completely chromium-free catalysts. This ensures that nitrogen determination in the laboratory is completely free of harmful substances. The analysis of liquid fertilizers using DumaSorb is also no problem. With the absorber, samples up to 100 mg are bound immediately and can then be analyzed without any problems. With the DUMATHERM fertilizers can be analyzed with the reference methods according to AOAC, DIN and VDLUFA.


For further information about the application DUMATHERM for nitrogen in fertilizer or a general application support please contact us via the contact form.