Glutamic acid and GABA are neurotransmitters. Glutamic acid and GABA are non-essential amino acids. They are hydrophilic and zwitter-ionic in nature . At lower pH, carboxylic acid groups of amino acids are not ionized, making them more hydrophobic and basic. Underivatized glutamic acid and GABA were retained and separated on a Primesep 100 column using ACN/water/TFA mobile phase. Amino acids can be monitored by low UV or ELSD/CAD. Retention is provided by reversed-phase and cation-exchange mechanism. Method can be used for analysis of underivatized amino acids in various matrices including supplements, vitamin and other complex mixtures. various mobile phase can be used with corresponding detection techniques.