Procedure

VN

Overview

The preparation of this document is based on a mandate given to CEN by the European Commission and the European Free Trade Association (mandate M/335) relating to the modernization of methods for the analysis of fertilizers within the scope of Regulation (EC) No 2003/2003. The document is part of a modular approach and concerns the analytical measurement step. "Modular" means that a test standard specifies a particular step in the assessment of a property and not the entire measurement chain. Although the determination of molybdenum in fertilizers is preferably carried out using ICP-AES according to prEN 16963:2016, the gravimetric method specified here is an option if ICP-AES is not available. This Technical Specification specifies a method for the determination of total and water extractable molybdenum in mineral fertilizers containing more than 10 % molybdenum. This method is applicable to water and aqua regia extracts of fertilizers obtained according to prEN 16962:2016 and/or prEN 16964:2016 and is based on the precipitation of molybdenum as molybdenum oxinate under the specified conditions. The precision of the method defined in this Technical Specification has been tested in a validation study under the direction of a consortium. A pan-European interlaboratory test could not be carried out as the method is only used in a few laboratories and a sufficient number of laboratories were not available. Within the validation study the method was verified against the determination of molybdenum using ICP-AES according to prEN 16963 when analyzing water and aqua regia extracts. It could be concluded that the method specified in this document for the determination of molybdenum in both extracts provides comparable results to the ICP-AES determination in the same extracts and that the gravimetric determination with hydroxyquinoline was successfully verified against a fully validated ICP-AES method according to prEN 16963. The statistical data of the validation study are given in Annex A. The draft of this European Technical Specification has been prepared in CEN/TC 260 "Fertilizers and lime fertilizers" (secretariat: DIN). National mirroring took place at Working Committee NA 057-03-02 AA "Düngemittel" ("Fertilizers") at DIN Standards Committee Food and Agricultural Products (NAL).

Document: references other documents

Responsible national committee

NA 057-03-02 AA - Fertilizers  

Responsible european committee

CEN/TC 260/WG 7 - Inorganic fertilizers and inhibitors