Selective separation of amino acids by reactive extraction

The method of reactive extraction with di-(2-ethylhexyl)phosphoric acid (D2EHPA) for the separation of a range of amino acids is studied. The results obtained on the individual reactive extraction indicated the possibility of the amino acids selective separation as a function of the pH value of aqueous solution and the acidic or basic character of each amino acid. Thus, using multistage extraction, the total separation of the following amino acids groups has been performed: neutral amino acids (L-glycine, L-alanine, L-tryptophan) at pH 5-5.5 (nine extraction stages), basic amino acids (L-lysine, L-arginine) and L-cysteine at pH 4-4.5 (ten extraction stages), L-histidine at pH 3-3.5 (five extraction stages), and acidic amino acids (L-aspartic acid, L-glutamic acid) at pH 2-2.5 (three extraction stages). (C) 2001 Elsevier Science B.V. All rights reserved.