This document specifies a spectrophotometric test method for the determination of free amino acid content in water-soluble fertilizers. This document is applicable to the determination of free amino acids in liquid or solid water-soluble fertilizers (Latu Fuan amino acid-containing water-soluble fertilizers and water-soluble fertilizers produced from alcohol waste liquid, molasses liquid, acidic amino acid raw powder, and alkaline amino acid raw powder). The principle is: use activated carbon to adsorb proteins and eliminate pigment interference, use EDTA to complex metal elements to release amino acids, and the amino acids react with ninhydrin to form blue substances. Within a certain concentration range, the absorbance of the blue solution is proportional to the amount of amino acids. , use spectrophotometry to measure the total amino acid content, and then divide it by the correction coefficient to get the free amino acid content.
T/GXAF 0010-2023 history
2023T/GXAF 0010-2023 Spectrophotometric method for the determination of free amino acid content in water-soluble fertilizers