DIN EN 16328:2013-02

The European Standard has been prepared by CEN/TC 260 "Fertilizers and liming materials" (secretariat: DIN) by Working Group WG 7 "Chemical analysis", with the active collaboration of German experts. The national committee acting as mirror committee is Working Committee NA 057-03-02 AA "Düngemittel" ("Fertilizers") at the Food and Agricultural Products Standards Committee (NAL). The standard contains a method for the determination of dimethylpyrazole phosphate (DMPP) in fertilizers. DMPP is a nitrification inhibitor. These substances delay the transformation of ammonium into nitrate in the soil. As a result, nitrate is transformed parallel to the needs of the plant from the existing ammonium and transferred to the plant. The yield is increased due to the steady release of the nitrogen. The nitrate levels in the crop are reduced and lower costs arise as the frequency of the fertilization and the dose rate of nitrate can be reduced without loss of earnings. The environment also benefits as the transfer of nitrate into the ground water is reduced and the formation of climate-relevant gases is diminished. The standard specifies a method for the determination of 3,4-dimethyl-1H-pyrazole phosphate (DMPP) in mineral N containing fertilizers using high-performance liquid chromatography (HPLC). The fertilizer sample is extracted in water; the concentration of DMPP is determined in the diluted aqueous solution by high performance liquid chromatography (HPLC) at a wavelength of 224 nm. The method has been validated in 2010 in a European inter-laboratory test with nine participating laboratories. The statistical results are given in informative Annex A. The project has been incorporated under the mandate M/418 upon application of a fertilizer manufacturer into the work programme of CEN/TC 260. It is the intention to adopt the nitrification inhibitor DMPP into the list of the approved fertilizer types of Regulation (EC) No 2003/2003 relating to fertilizers. An essential prerequisite for this listing is a validated method of analysis which has been specified in a European Standard.