ISO 19746:2017 specifies the test procedure for determining the urea content in urea-based fertilizers, including urea, urea aldehydes [methylene urea fertilizers, isobutylene diurea (IBDU), crotonylidene diurea (CDU)], urea triazone fertilizers, urea ammonium nitrate (UAN), sulfur- and polymer-coated urea (SCU and PCU), as well as compound fertilizers containing urea. The method is based on High Performance Liquid Chromatography (HPLC).
The proposed method is an extension of the AOAC Official Method 2003.14 which was collaboratively studied for the "Determination of Urea in Water-Soluble Urea-Formaldehyde Fertilizer Products and in Aqueous Urea Solutions" in 2003. The method was published in the Journal of AOAC in 2004 and was granted the First Action in 2003 and the Final Action in 2008.
This method also applies to the determination of biuret content in urea containing fertilizer with the results published in the J. AOAC in 2014. This method was adopted by the International Organization for Standardization (ISO) as a Committee Draft (ISO/CD 18643) in 2014, and after review and the Ring Test Analyses.