ISO/DIS 25300

This document specifies the methods for determining the content of free amino acids in fertilizers, including the use of automatic amino acid analyzers, pre-column derivatization followed by high-performance liquid chromatography and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS). These methods are applicable to the following amino acids: Asparagine Tryptophan, Glutamine, Theanine, Aspartic acid, Threonine, Serine, Glutamic acid, Proline, Glycine, Alanine, Valine, Methionine, Isoleucine, Leucine, Tyrosine, Phenylalanine, Histidine, Lysine, Arginine, and Cysteine.