|Molecular Weight||174.204 g/mol|
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).
Glutamine, valine, isoleucine, and leucine are baseline resolved in a dietary supplement with a mobile phase of acetonitrile, water, and sulfuric acid with ultraviolet (UV) detection at 210 nm on a Primesep 100 column. Increasing the sulfuric acid concentration allows elution of arginine. Primesep 100 separates underivatized amino acids and amines by combining reversed-phase and ion-exchange mechanisms. The HPLC separation uses a mobile phase of water, acetonitrile (MeCN, ACN), and sulfuric acid with ultraviolet (UV) detection at 210 nm.
Polar amino acids are very often used as components of vitamin and supplement composition. Analysis of such complex composition is a challenging task. In this application, 5 amino acids (asparagine, glutamic acid, proline and arginine) and two preservatives (methyl paraben and propyl paraben) are separated on a Primesep 100 reversed-phase cation-exchange column with LC/MS compatible mobile phase. Method does not require ion-pairing reagent in the mobile phase. Compounds are monitored by ELSD and UV. Method is validated for quantitation of underivatized amino acids in complex mixtures. The method is simple and robust and can be used for analysis of various vitamin formulations.
Two underivatized amino acids, citrulline and arginine, are separated by mixed-mode chromatography on Primesep 100 and Primesep 200 HPLC columns with LC/MS compatible mobile phase. Method can be used for retention and separation of underivatized amino acids without ion-pairing reagent in the mobile phase.
Application Notes: Amino acids are polar ionic compounds which are not retained on reversed-phase column without ion-pairing reagent. In our application, lysine and arginine can be separated from other amino acids. Amino acids with a pH between 3 and 5 and with one basic and one acidic group become very polar. Therefore these amino acids don’t have strong ion-exchange interaction with Primesep C stationary phase. Amino acids with two amino groups still carry positive net charge and can interact with stationary phase by cations-exchange mechanism. pH variation of the mobile phase can be an effective tool to adjust selectivity of separation for zwitter-ionic, basic and acidic compounds. This method can be used for separation of mono-charged compounds from compounds having an extra charge.
Application Columns: Primesep C
Application compounds: Aspartic acid, Glutamic acid, Aspargine, Glycine, Proline, Alanine, Phenylalanine, Tyrosine, Leucine, Lysine, Arginine
Detection technique: UV, LC/MS, ELSD/CAD