Amino Acids Analysis in Acid Gradient Condition

11 underivatized amino acids (aspartic acid, glutamic acid, alanine, valine, methionine, isoleucine, cysteine, phenylalanine, histidine, lysine, and arginine) are separated by a Primesep 100 HPLC column by reversed-phase and ion-exchange mechanisms with LC/MS compatible conditions without the use of ion-pair reagents. The HPLC separation uses a TFA (trifluoroacetic acid) gradient in a mobile phase of water acetonitrile (MeCN, ACN with evaporative light scattering detection (ELSD).