This International Standard specifies a method for the quantitative determination of free (non-protein bound) lysine, methionine and threonine in commercial products and premixtures containing more than about 10% by weight of the corresponding amino acid. It does not differentiate between D and L shapes. NOTE For the purposes of this International Standard, the term "amino acids" used in Section 2 and following refers to lysine, methionine and threonine.
EN ISO 17180:2013 history
2013EN ISO 17180:2013 Animal feeding stuffs - Determination of lysine@ methionine and threonine in commercial amino acid products and premixtures