DS EN 16075:2011 Fertilizers - Determination Of N-(2-Nitrophenyl)Phosphoric Triamide (2-Npt) In Urea And Fertilizers Containing Urea - Method Using High-Performance Liquid Chromatography (Hplc) Defines a method for the determination of N-(2-nitrophenyl)phosphoric triamide (2-NPT) in urea or in fertilizers containing urea using high-performance liquid chromatography (HPLC).